21008215024 has 20 divisors (see below), whose sum is σ = 40708214944. Its totient is φ = 10502869248.

The previous prime is 21008214979. The next prime is 21008215027. The reversal of 21008215024 is 42051280012.

It is a self number, because there is not a number n which added to its sum of digits gives 21008215024.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21008215027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71224 + ... + 217000.

Almost surely, 2^21008215024 is an apocalyptic number.

It is an amenable number.

21008215024 is a deficient number, since it is larger than the sum of its proper divisors (19699999920).

21008215024 is a wasteful number, since it uses less digits than its factorization.

21008215024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154792 (or 154786 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 25.

Adding to 21008215024 its reverse (42051280012), we get a palindrome (63059495036).

The spelling of 21008215024 in words is "twenty-one billion, eight million, two hundred fifteen thousand, twenty-four".