21021504784 has 40 divisors (see below), whose sum is σ = 46557357440. Its totient is φ = 9007331328.

The previous prime is 21021504761. The next prime is 21021504821. The reversal of 21021504784 is 48740512012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 606877 + ... + 640579.

It is an arithmetic number, because the mean of its divisors is an integer number (1163933936).

Almost surely, 2^21021504784 is an apocalyptic number.

It is an amenable number.

21021504784 is an abundant number, since it is smaller than the sum of its proper divisors (25535852656).

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

21021504784 is a wasteful number, since it uses less digits than its factorization.

21021504784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39287 (or 39281 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 34.

The spelling of 21021504784 in words is "twenty-one billion, twenty-one million, five hundred four thousand, seven hundred eighty-four".