61556585968640 has 704 divisors, whose sum is σ = 173787893121024. Its totient is φ = 20487364411392.

The previous prime is 61556585968561. The next prime is 61556585968673. The reversal of 61556585968640 is 4686958565516.

It is a super-2 number, since 2×61556585968640² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 101411179217 + ... + 101411179823.

Almost surely, 2^{61556585968640} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61556585968640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86893946560512).

61556585968640 is an abundant number, since it is smaller than the sum of its proper divisors (112231307152384).

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

61556585968640 is a wasteful number, since it uses less digits than its factorization.

61556585968640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1262 (or 1244 counting only the distinct ones).

The product of its (nonzero) digits is 1866240000, while the sum is 74.

The spelling of 61556585968640 in words is "sixty-one trillion, five hundred fifty-six billion, five hundred eighty-five million, nine hundred sixty-eight thousand, six hundred forty".