21523310404 has 12 divisors (see below), whose sum is σ = 38683787884. Its totient is φ = 10470799584.

The previous prime is 21523310381. The next prime is 21523310477. The reversal of 21523310404 is 40401332512.

It can be written as a sum of positive squares in 2 ways, for example, as 16320573504 + 5202736900 = 127752^2 + 72130^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72713739 + ... + 72714034.

Almost surely, 2^21523310404 is an apocalyptic number.

It is an amenable number.

21523310404 is a deficient number, since it is larger than the sum of its proper divisors (17160477480).

21523310404 is a wasteful number, since it uses less digits than its factorization.

21523310404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145427814 (or 145427812 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

Adding to 21523310404 its reverse (40401332512), we get a palindrome (61924642916).

The spelling of 21523310404 in words is "twenty-one billion, five hundred twenty-three million, three hundred ten thousand, four hundred four".