61191408240 has 480 divisors, whose sum is σ = 218577528000. Its totient is φ = 15317729280.

The previous prime is 61191408233. The next prime is 61191408241. The reversal of 61191408240 is 4280419116.

61191408240 is a `hidden beast` number, since 6 + 1 + 1 + 9 + 1 + 408 + 240 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 61191408195 and 61191408204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61191408241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 136283536 + ... + 136283984.

It is an arithmetic number, because the mean of its divisors is an integer number (455369850).

Almost surely, 2^61191408240 is an apocalyptic number.

61191408240 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 61191408240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109288764000).

61191408240 is an abundant number, since it is smaller than the sum of its proper divisors (157386119760).

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

61191408240 is a wasteful number, since it uses less digits than its factorization.

61191408240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665 (or 656 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The spelling of 61191408240 in words is "sixty-one billion, one hundred ninety-one million, four hundred eight thousand, two hundred forty".