21321068544 has 78 divisors (see below), whose sum is σ = 61586785676. Its totient is φ = 7107010560.

The previous prime is 21321068533. The next prime is 21321068581. The reversal of 21321068544 is 44586012312.

It is a happy number.

21321068544 is a `hidden beast` number, since 2 + 1 + 3 + 2 + 106 + 8 + 544 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21321068499 and 21321068508.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 252322 + ... + 326049.

Almost surely, 2^21321068544 is an apocalyptic number.

21321068544 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21321068544 is an abundant number, since it is smaller than the sum of its proper divisors (40265717132).

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

21321068544 is an equidigital number, since it uses as much as digits as its factorization.

21321068544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 578401 (or 578376 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The spelling of 21321068544 in words is "twenty-one billion, three hundred twenty-one million, sixty-eight thousand, five hundred forty-four".