19976712921 has 27 divisors (see below), whose sum is σ = 31724336917. Its totient is φ = 12104271960.

The previous prime is 19976712887. The next prime is 19976712929. The reversal of 19976712921 is 12921767991.

The square root of 19976712921 is 141339.

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

It is not a de Polignac number, because 19976712921 - 2⁹ = 19976712409 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19976712929) 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, 4662046 + ... + 4666328.

Almost surely, 2^19976712921 is an apocalyptic number.

19976712921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

19976712921 is the 141339-th square number.

19976712921 is the 70670-th centered octagonal number.

It is an amenable number.

19976712921 is a deficient number, since it is larger than the sum of its proper divisors (11747623996).

19976712921 is an frugal number, since it uses more digits than its factorization.

19976712921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8594 (or 4297 counting only the distinct ones).

The product of its digits is 857304, while the sum is 54.

The spelling of 19976712921 in words is "nineteen billion, nine hundred seventy-six million, seven hundred twelve thousand, nine hundred twenty-one".