21860961984 has 84 divisors (see below), whose sum is σ = 65384909616. Its totient is φ = 6970157568.

The previous prime is 21860961959. The next prime is 21860961989. The reversal of 21860961984 is 48916906812.

21860961984 is a `hidden beast` number, since 2 + 18 + 6 + 0 + 9 + 619 + 8 + 4 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21860961984.

It is not an unprimeable number, because it can be changed into a prime (21860961989) 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, 811819 + ... + 838314.

Almost surely, 2^21860961984 is an apocalyptic number.

21860961984 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21860961984 is an abundant number, since it is smaller than the sum of its proper divisors (43523947632).

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

21860961984 is a wasteful number, since it uses less digits than its factorization.

21860961984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1650174 (or 1650161 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 54.

The spelling of 21860961984 in words is "twenty-one billion, eight hundred sixty million, nine hundred sixty-one thousand, nine hundred eighty-four".