61813900644 has 48 divisors (see below), whose sum is σ = 146847546048. Its totient is φ = 20232989568.

The previous prime is 61813900637. The next prime is 61813900679. The reversal of 61813900644 is 44600931816.

It is a super-2 number, since 2×61813900644² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 61813900596 and 61813900605.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 133602 + ... + 376134.

It is an arithmetic number, because the mean of its divisors is an integer number (3059323876).

Almost surely, 2^61813900644 is an apocalyptic number.

It is an amenable number.

61813900644 is an abundant number, since it is smaller than the sum of its proper divisors (85033645404).

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

61813900644 is a wasteful number, since it uses less digits than its factorization.

61813900644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242924 (or 242922 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 42.

The spelling of 61813900644 in words is "sixty-one billion, eight hundred thirteen million, nine hundred thousand, six hundred forty-four".