15718561 has 2 divisors, whose sum is σ = 15718562. Its totient is φ = 15718560.

The previous prime is 15718553. The next prime is 15718589. The reversal of 15718561 is 16581751.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15358561 + 360000 = 3919^2 + 600^2 .

It is a cyclic number.

It is not a de Polignac number, because 15718561 - 2³ = 15718553 is a prime.

It is not a weakly prime, because it can be changed into another prime (15718501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7859280 + 7859281.

It is an arithmetic number, because the mean of its divisors is an integer number (7859281).

Almost surely, 2^15718561 is an apocalyptic number.

It is an amenable number.

15718561 is a deficient number, since it is larger than the sum of its proper divisors (1).

15718561 is an equidigital number, since it uses as much as digits as its factorization.

15718561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8400, while the sum is 34.

The square root of 15718561 is about 3964.6640462970. The cubic root of 15718561 is about 250.4979993280.

The spelling of 15718561 in words is "fifteen million, seven hundred eighteen thousand, five hundred sixty-one".