21020169724 has 24 divisors (see below), whose sum is σ = 39014021088. Its totient is φ = 9875366400.

The previous prime is 21020169701. The next prime is 21020169743. The reversal of 21020169724 is 42796102012.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a self number, because there is not a number n which added to its sum of digits gives 21020169724.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 216304 + ... + 298039.

It is an arithmetic number, because the mean of its divisors is an integer number (1625584212).

Almost surely, 2^21020169724 is an apocalyptic number.

It is an amenable number.

21020169724 is a deficient number, since it is larger than the sum of its proper divisors (17993851364).

21020169724 is a wasteful number, since it uses less digits than its factorization.

21020169724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 514965 (or 514963 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 34.

The spelling of 21020169724 in words is "twenty-one billion, twenty million, one hundred sixty-nine thousand, seven hundred twenty-four".