61640510778 has 48 divisors (see below), whose sum is σ = 166509435456. Its totient is φ = 16010521920.

The previous prime is 61640510719. The next prime is 61640510791. The reversal of 61640510778 is 87701504616.

61640510778 is a `hidden beast` number, since 6 + 1 + 64 + 0 + 510 + 7 + 78 = 666.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 22235451 + ... + 22238222.

It is an arithmetic number, because the mean of its divisors is an integer number (3468946572).

Almost surely, 2^61640510778 is an apocalyptic number.

61640510778 is an abundant number, since it is smaller than the sum of its proper divisors (104868924678).

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

61640510778 is a wasteful number, since it uses less digits than its factorization.

61640510778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44473699 (or 44473696 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 45.

The spelling of 61640510778 in words is "sixty-one billion, six hundred forty million, five hundred ten thousand, seven hundred seventy-eight".