21500945424 has 80 divisors (see below), whose sum is σ = 70532211840. Its totient is φ = 6143126400.

The previous prime is 21500945393. The next prime is 21500945437. The reversal of 21500945424 is 42454900512.

It is a happy number.

21500945424 is a `hidden beast` number, since 21 + 5 + 0 + 0 + 94 + 542 + 4 = 666.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3552027 + ... + 3558074.

It is an arithmetic number, because the mean of its divisors is an integer number (881652648).

Almost surely, 2^21500945424 is an apocalyptic number.

21500945424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21500945424 is an abundant number, since it is smaller than the sum of its proper divisors (49031266416).

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

21500945424 is a wasteful number, since it uses less digits than its factorization.

21500945424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7110125 (or 7110113 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The spelling of 21500945424 in words is "twenty-one billion, five hundred million, nine hundred forty-five thousand, four hundred twenty-four".