13579721 has 2 divisors, whose sum is σ = 13579722. Its totient is φ = 13579720.

The previous prime is 13579697. The next prime is 13579781. The reversal of 13579721 is 12797531.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12996025 + 583696 = 3605^2 + 764^2 .

It is a cyclic number.

It is not a de Polignac number, because 13579721 - 2²² = 9385417 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (13579781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6789860 + 6789861.

It is an arithmetic number, because the mean of its divisors is an integer number (6789861).

Almost surely, 2^13579721 is an apocalyptic number.

It is an amenable number.

13579721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13579721 is an equidigital number, since it uses as much as digits as its factorization.

13579721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13230, while the sum is 35.

The square root of 13579721 is about 3685.0672992498. The cubic root of 13579721 is about 238.5779389484.

The spelling of 13579721 in words is "thirteen million, five hundred seventy-nine thousand, seven hundred twenty-one".