21521040424 has 32 divisors (see below), whose sum is σ = 43462782720. Its totient is φ = 9931225536.

The previous prime is 21521040391. The next prime is 21521040439. The reversal of 21521040424 is 42404012512.

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, 889009 + ... + 912895.

It is an arithmetic number, because the mean of its divisors is an integer number (1358211960).

Almost surely, 2^21521040424 is an apocalyptic number.

It is an amenable number.

21521040424 is an abundant number, since it is smaller than the sum of its proper divisors (21941742296).

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

21521040424 is a wasteful number, since it uses less digits than its factorization.

21521040424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32569 (or 32565 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 25.

Adding to 21521040424 its reverse (42404012512), we get a palindrome (63925052936).

The spelling of 21521040424 in words is "twenty-one billion, five hundred twenty-one million, forty thousand, four hundred twenty-four".