21505432364 has 24 divisors (see below), whose sum is σ = 40552760640. Its totient is φ = 9919880064.

The previous prime is 21505432363. The next prime is 21505432391. The reversal of 21505432364 is 46323450512.

It is not an unprimeable number, because it can be changed into a prime (21505432363) 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, 26804 + ... + 209115.

It is an arithmetic number, because the mean of its divisors is an integer number (1689698360).

Almost surely, 2^21505432364 is an apocalyptic number.

It is an amenable number.

21505432364 is a deficient number, since it is larger than the sum of its proper divisors (19047328276).

21505432364 is a wasteful number, since it uses less digits than its factorization.

21505432364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237689 (or 237687 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 35.

Adding to 21505432364 its reverse (46323450512), we get a palindrome (67828882876).

The spelling of 21505432364 in words is "twenty-one billion, five hundred five million, four hundred thirty-two thousand, three hundred sixty-four".