61651338840 has 640 divisors, whose sum is σ = 256503582720. Its totient is φ = 12933043200.

The previous prime is 61651338821. The next prime is 61651338857. The reversal of 61651338840 is 4883315616.

61651338840 is a `hidden beast` number, since 6 + 16 + 513 + 3 + 88 + 40 = 666.

61651338840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 62210745 + ... + 62211735.

It is an arithmetic number, because the mean of its divisors is an integer number (400786848).

Almost surely, 2^61651338840 is an apocalyptic number.

61651338840 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 61651338840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128251791360).

61651338840 is an abundant number, since it is smaller than the sum of its proper divisors (194852243880).

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

61651338840 is a wasteful number, since it uses less digits than its factorization.

61651338840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1245 (or 1232 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 45.

The spelling of 61651338840 in words is "sixty-one billion, six hundred fifty-one million, three hundred thirty-eight thousand, eight hundred forty".