61686396858240 has 2560 divisors, whose sum is σ = 279809925120000. Its totient is φ = 12579293675520.

The previous prime is 61686396858217. The next prime is 61686396858263. The reversal of 61686396858240 is 4285869368616.

61686396858240 is a `hidden beast` number, since 6 + 1 + 6 + 8 + 6 + 39 + 6 + 8 + 582 + 4 + 0 = 666.

61686396858240 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (61686396858217) and next prime (61686396858263).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 62753200789 + ... + 62753201771.

It is an arithmetic number, because the mean of its divisors is an integer number (109300752000).

Almost surely, 2^{61686396858240} is an apocalyptic number.

61686396858240 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61686396858240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139904962560000).

61686396858240 is an abundant number, since it is smaller than the sum of its proper divisors (218123528261760).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61686396858240 is a wasteful number, since it uses less digits than its factorization.

61686396858240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1310 (or 1289 counting only the distinct ones).

The product of its (nonzero) digits is 716636160, while the sum is 72.

The spelling of 61686396858240 in words is "sixty-one trillion, six hundred eighty-six billion, three hundred ninety-six million, eight hundred fifty-eight thousand, two hundred forty".