61431558864 has 160 divisors (see below), whose sum is σ = 181113408000. Its totient is φ = 17804881920.

The previous prime is 61431558863. The next prime is 61431558869. The reversal of 61431558864 is 46885513416.

It is a happy number.

61431558864 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×61431558864² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61431558863) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 700537 + ... + 783335.

It is an arithmetic number, because the mean of its divisors is an integer number (1131958800).

Almost surely, 2^61431558864 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 61431558864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90556704000).

61431558864 is an abundant number, since it is smaller than the sum of its proper divisors (119681849136).

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

61431558864 is a wasteful number, since it uses less digits than its factorization.

61431558864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82893 (or 82887 counting only the distinct ones).

The product of its digits is 2764800, while the sum is 51.

The spelling of 61431558864 in words is "sixty-one billion, four hundred thirty-one million, five hundred fifty-eight thousand, eight hundred sixty-four".