21520351504 has 40 divisors (see below), whose sum is σ = 42547770072. Its totient is φ = 10540907520.

The previous prime is 21520351499. The next prime is 21520351579. The reversal of 21520351504 is 40515302512.

It can be written as a sum of positive squares in 4 ways, for example, as 6231523600 + 15288827904 = 78940^2 + 123648^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 541332 + ... + 579724.

Almost surely, 2^21520351504 is an apocalyptic number.

It is an amenable number.

21520351504 is a deficient number, since it is larger than the sum of its proper divisors (21027418568).

21520351504 is a wasteful number, since it uses less digits than its factorization.

21520351504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39115 (or 39109 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 28.

The spelling of 21520351504 in words is "twenty-one billion, five hundred twenty million, three hundred fifty-one thousand, five hundred four".