19538727961 has 9 divisors (see below), whose sum is σ = 19729116381. Its totient is φ = 19350163392.

The previous prime is 19538727947. The next prime is 19538728043. The reversal of 19538727961 is 16972783591.

The square root of 19538727961 is 139781.

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

It can be written as a sum of positive squares in 4 ways, for example, as 2747751561 + 16790976400 = 52419^2 + 129580^2 .

It is a de Polignac number, because none of the positive numbers 2^k-19538727961 is a prime.

It is a super-3 number, since 3×19538727961³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19538727896 and 19538727905.

It is not an unprimeable number, because it can be changed into a prime (19538727661) 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, 15794635 + ... + 15795871.

Almost surely, 2^19538727961 is an apocalyptic number.

19538727961 is the 139781-st square number.

19538727961 is the 69891-st centered octagonal number.

It is an amenable number.

19538727961 is a deficient number, since it is larger than the sum of its proper divisors (190388420).

19538727961 is an frugal number, since it uses more digits than its factorization.

19538727961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2700 (or 1350 counting only the distinct ones).

The product of its digits is 5715360, while the sum is 58.

The spelling of 19538727961 in words is "nineteen billion, five hundred thirty-eight million, seven hundred twenty-seven thousand, nine hundred sixty-one".