15913561 has 2 divisors, whose sum is σ = 15913562. Its totient is φ = 15913560.

The previous prime is 15913549. The next prime is 15913567. The reversal of 15913561 is 16531951.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8179600 + 7733961 = 2860^2 + 2781^2 .

It is a cyclic number.

It is not a de Polignac number, because 15913561 - 2¹¹ = 15911513 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (15913567) 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, 7956780 + 7956781.

It is an arithmetic number, because the mean of its divisors is an integer number (7956781).

Almost surely, 2^15913561 is an apocalyptic number.

It is an amenable number.

15913561 is a deficient number, since it is larger than the sum of its proper divisors (1).

15913561 is an equidigital number, since it uses as much as digits as its factorization.

15913561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4050, while the sum is 31.

The square root of 15913561 is about 3989.1804922816. The cubic root of 15913561 is about 251.5296140363.

The spelling of 15913561 in words is "fifteen million, nine hundred thirteen thousand, five hundred sixty-one".