19337961721 has 27 divisors (see below), whose sum is σ = 22139353359. Its totient is φ = 16880892912.

The previous prime is 19337961719. The next prime is 19337961751. The reversal of 19337961721 is 12716973391.

The square root of 19337961721 is 139061.

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

It can be written as a sum of positive squares in only one way, i.e., 2860645225 + 16477316496 = 53485^2 + 128364^2 .

It is not a de Polignac number, because 19337961721 - 2¹ = 19337961719 is a prime.

It is a super-2 number, since 2×19337961721² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19337961701) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 34347786 + ... + 34348348.

Almost surely, 2^19337961721 is an apocalyptic number.

19337961721 is the 139061-st square number.

19337961721 is the 69531-st centered octagonal number.

It is an amenable number.

19337961721 is a deficient number, since it is larger than the sum of its proper divisors (2801391638).

19337961721 is an frugal number, since it uses more digits than its factorization.

19337961721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1190 (or 595 counting only the distinct ones).

The product of its digits is 428652, while the sum is 49.

Multiplying 19337961721 by its sum of digits (49), we get a square (947560124329 = 973427²).

The spelling of 19337961721 in words is "nineteen billion, three hundred thirty-seven million, nine hundred sixty-one thousand, seven hundred twenty-one".