19976975532721 has 3 divisors (see below), whose sum is σ = 19976980002283. Its totient is φ = 19976971063160.

The previous prime is 19976975532677. The next prime is 19976975532779. The reversal of 19976975532721 is 12723557967991.

The square root of 19976975532721 is 4469561.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 2603417747121 + 17373557785600 = 1613511^2 + 4168160^2 .

It is not a de Polignac number, because 19976975532721 - 2¹³ = 19976975524529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19976979532721) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2234781 + ... + 6704341.

Almost surely, 2^{19976975532721} is an apocalyptic number.

19976975532721 is the 4469561-st square number.

19976975532721 is the 2234781-st centered octagonal number.

It is an amenable number.

19976975532721 is a deficient number, since it is larger than the sum of its proper divisors (4469562).

19976975532721 is an frugal number, since it uses more digits than its factorization.

19976975532721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8939122 (or 4469561 counting only the distinct ones).

The product of its digits is 450084600, while the sum is 73.

The spelling of 19976975532721 in words is "nineteen trillion, nine hundred seventy-six billion, nine hundred seventy-five million, five hundred thirty-two thousand, seven hundred twenty-one".