61920209664 has 108 divisors (see below), whose sum is σ = 178600190496. Its totient is φ = 20632098816.

The previous prime is 61920209653. The next prime is 61920209707. The reversal of 61920209664 is 46690202916.

61920209664 is a `hidden beast` number, since 619 + 2 + 0 + 20 + 9 + 6 + 6 + 4 = 666.

61920209664 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 2×61920209664² (a number of 22 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11385954 + ... + 11391390.

Almost surely, 2^61920209664 is an apocalyptic number.

61920209664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61920209664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89300095248).

61920209664 is an abundant number, since it is smaller than the sum of its proper divisors (116679980832).

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

61920209664 is a wasteful number, since it uses less digits than its factorization.

61920209664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10402 (or 10385 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The spelling of 61920209664 in words is "sixty-one billion, nine hundred twenty million, two hundred nine thousand, six hundred sixty-four".