19962581521 has 9 divisors (see below), whose sum is σ = 20871653929. Its totient is φ = 19091534836.

The previous prime is 19962581503. The next prime is 19962581537. The reversal of 19962581521 is 12518526991.

The square root of 19962581521 is 141289.

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

It is not a de Polignac number, because 19962581521 - 2¹³ = 19962573329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19362581521) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3246576 + ... + 3252718.

Almost surely, 2^19962581521 is an apocalyptic number.

19962581521 is the 141289-th square number.

19962581521 is the 70645-th centered octagonal number.

It is an amenable number.

19962581521 is a deficient number, since it is larger than the sum of its proper divisors (909072408).

19962581521 is an frugal number, since it uses more digits than its factorization.

19962581521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12332 (or 6166 counting only the distinct ones).

The product of its digits is 388800, while the sum is 49.

Multiplying 19962581521 by its sum of digits (49), we get a square (978166494529 = 989023²).

The spelling of 19962581521 in words is "nineteen billion, nine hundred sixty-two million, five hundred eighty-one thousand, five hundred twenty-one".