16572316721 has 2 divisors, whose sum is σ = 16572316722. Its totient is φ = 16572316720.

The previous prime is 16572316699. The next prime is 16572316723. The reversal of 16572316721 is 12761327561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16266451600 + 305865121 = 127540^2 + 17489^2 .

It is a cyclic number.

It is not a de Polignac number, because 16572316721 - 2¹⁴ = 16572300337 is a prime.

It is a super-2 number, since 2×16572316721² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 16572316723, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (16572316723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8286158360 + 8286158361.

It is an arithmetic number, because the mean of its divisors is an integer number (8286158361).

Almost surely, 2^16572316721 is an apocalyptic number.

It is an amenable number.

16572316721 is a deficient number, since it is larger than the sum of its proper divisors (1).

16572316721 is an equidigital number, since it uses as much as digits as its factorization.

16572316721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 105840, while the sum is 41.

The spelling of 16572316721 in words is "sixteen billion, five hundred seventy-two million, three hundred sixteen thousand, seven hundred twenty-one".