21513404404 has 24 divisors (see below), whose sum is σ = 38035331208. Its totient is φ = 10646246400.

The previous prime is 21513404401. The next prime is 21513404441. The reversal of 21513404404 is 40440431512.

It can be written as a sum of positive squares in 4 ways, for example, as 18840307600 + 2673096804 = 137260^2 + 51702^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21513404401) 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, 1291392 + ... + 1307944.

It is an arithmetic number, because the mean of its divisors is an integer number (1584805467).

Almost surely, 2^21513404404 is an apocalyptic number.

It is an amenable number.

21513404404 is a deficient number, since it is larger than the sum of its proper divisors (16521926804).

21513404404 is a wasteful number, since it uses less digits than its factorization.

21513404404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19875 (or 19873 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 28.

Adding to 21513404404 its reverse (40440431512), we get a palindrome (61953835916).

The spelling of 21513404404 in words is "twenty-one billion, five hundred thirteen million, four hundred four thousand, four hundred four".