21684645492608 has 64 divisors (see below), whose sum is σ = 49470232560000. Its totient is φ = 9274795218432.

The previous prime is 21684645492599. The next prime is 21684645492673. The reversal of 21684645492608 is 80629454648612.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23803010 + ... + 24697217.

It is an arithmetic number, because the mean of its divisors is an integer number (772972383750).

Almost surely, 2^{21684645492608} is an apocalyptic number.

21684645492608 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21684645492608 is an abundant number, since it is smaller than the sum of its proper divisors (27785587067392).

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

21684645492608 is an equidigital number, since it uses as much as digits as its factorization.

21684645492608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48500747 (or 48500735 counting only the distinct ones).

The product of its (nonzero) digits is 159252480, while the sum is 65.

The spelling of 21684645492608 in words is "twenty-one trillion, six hundred eighty-four billion, six hundred forty-five million, four hundred ninety-two thousand, six hundred eight".