21390657824 has 48 divisors (see below), whose sum is σ = 44344288800. Its totient is φ = 10128996864.

The previous prime is 21390657811. The next prime is 21390657829. The reversal of 21390657824 is 42875609312.

It is not an unprimeable number, because it can be changed into a prime (21390657829) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3437564 + ... + 3443780.

It is an arithmetic number, because the mean of its divisors is an integer number (923839350).

It is a 1-persistent number, because it is pandigital, but 2⋅21390657824 = 42781315648 is not.

Almost surely, 2^21390657824 is an apocalyptic number.

It is an amenable number.

21390657824 is an abundant number, since it is smaller than the sum of its proper divisors (22953630976).

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

21390657824 is a wasteful number, since it uses less digits than its factorization.

21390657824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11905 (or 11897 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 47.

The spelling of 21390657824 in words is "twenty-one billion, three hundred ninety million, six hundred fifty-seven thousand, eight hundred twenty-four".