21521476804 has 9 divisors (see below), whose sum is σ = 37663097871. Its totient is φ = 10760591700.

The previous prime is 21521476789. The next prime is 21521476817. The reversal of 21521476804 is 40867412512.

The square root of 21521476804 is 146702.

It is a perfect power (a square), and thus also a powerful number.

It is a super-2 number, since 2×21521476804² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 256729 + ... + 330079.

Almost surely, 2^21521476804 is an apocalyptic number.

21521476804 is the 146702-nd square number.

It is an amenable number.

21521476804 is a deficient number, since it is larger than the sum of its proper divisors (16141621067).

21521476804 is an frugal number, since it uses more digits than its factorization.

21521476804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146706 (or 73353 counting only the distinct ones).

The product of its (nonzero) digits is 107520, while the sum is 40.

The spelling of 21521476804 in words is "twenty-one billion, five hundred twenty-one million, four hundred seventy-six thousand, eight hundred four".