19916604864 has 224 divisors, whose sum is σ = 66765464640. Its totient is φ = 5767593984.

The previous prime is 19916604857. The next prime is 19916604887. The reversal of 19916604864 is 46840661991.

It is a happy number.

19916604864 is a `hidden beast` number, since 1 + 99 + 16 + 60 + 486 + 4 = 666.

It is a super-2 number, since 2×19916604864² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 19916604864.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 355812 + ... + 407964.

It is an arithmetic number, because the mean of its divisors is an integer number (298060110).

Almost surely, 2^19916604864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19916604864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33382732320).

19916604864 is an abundant number, since it is smaller than the sum of its proper divisors (46848859776).

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

19916604864 is a wasteful number, since it uses less digits than its factorization.

19916604864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52204 (or 52188 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 54.

The spelling of 19916604864 in words is "nineteen billion, nine hundred sixteen million, six hundred four thousand, eight hundred sixty-four".