21216262464 has 84 divisors (see below), whose sum is σ = 60843444480. Its totient is φ = 7068499200.

The previous prime is 21216262421. The next prime is 21216262481. The reversal of 21216262464 is 46426261212.

21216262464 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 626 + 24 + 6 + 4 = 666.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

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, 1281439 + ... + 1297889.

It is an arithmetic number, because the mean of its divisors is an integer number (724326720).

Almost surely, 2^21216262464 is an apocalyptic number.

21216262464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21216262464 is an abundant number, since it is smaller than the sum of its proper divisors (39627182016).

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

21216262464 is a wasteful number, since it uses less digits than its factorization.

21216262464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18708 (or 18695 counting only the distinct ones).

The product of its digits is 55296, while the sum is 36.

The spelling of 21216262464 in words is "twenty-one billion, two hundred sixteen million, two hundred sixty-two thousand, four hundred sixty-four".