61017988644 has 36 divisors (see below), whose sum is σ = 160946001216. Its totient is φ = 19455010608.

The previous prime is 61017988643. The next prime is 61017988657. The reversal of 61017988644 is 44688971016.

61017988644 is a `hidden beast` number, since 610 + 17 + 9 + 8 + 8 + 6 + 4 + 4 = 666.

61017988644 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (61017988643) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 36845784 + ... + 36847439.

It is an arithmetic number, because the mean of its divisors is an integer number (4470722256).

Almost surely, 2^61017988644 is an apocalyptic number.

It is an amenable number.

61017988644 is an abundant number, since it is smaller than the sum of its proper divisors (99928012572).

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

61017988644 is a wasteful number, since it uses less digits than its factorization.

61017988644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73693256 (or 73693251 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 54.

The spelling of 61017988644 in words is "sixty-one billion, seventeen million, nine hundred eighty-eight thousand, six hundred forty-four".