15922721 has 2 divisors, whose sum is σ = 15922722. Its totient is φ = 15922720.

The previous prime is 15922679. The next prime is 15922729. The reversal of 15922721 is 12722951.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10923025 + 4999696 = 3305^2 + 2236^2 .

It is a cyclic number.

It is not a de Polignac number, because 15922721 - 2¹⁸ = 15660577 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (15922729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7961360 + 7961361.

It is an arithmetic number, because the mean of its divisors is an integer number (7961361).

Almost surely, 2^15922721 is an apocalyptic number.

It is an amenable number.

15922721 is a deficient number, since it is larger than the sum of its proper divisors (1).

15922721 is an equidigital number, since it uses as much as digits as its factorization.

15922721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2520, while the sum is 29.

The square root of 15922721 is about 3990.3284325980. The cubic root of 15922721 is about 251.5778657409.

The spelling of 15922721 in words is "fifteen million, nine hundred twenty-two thousand, seven hundred twenty-one".