61781918816 has 12 divisors (see below), whose sum is σ = 121633152732. Its totient is φ = 30890959392.

The previous prime is 61781918791. The next prime is 61781918833. The reversal of 61781918816 is 61881918716.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 965342450 + ... + 965342513.

It is an arithmetic number, because the mean of its divisors is an integer number (10136096061).

Almost surely, 2^61781918816 is an apocalyptic number.

It is an amenable number.

61781918816 is a deficient number, since it is larger than the sum of its proper divisors (59851233916).

61781918816 is a wasteful number, since it uses less digits than its factorization.

61781918816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1930684973 (or 1930684965 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 56.

The spelling of 61781918816 in words is "sixty-one billion, seven hundred eighty-one million, nine hundred eighteen thousand, eight hundred sixteen".