15256651661 has 2 divisors, whose sum is σ = 15256651662. Its totient is φ = 15256651660.

The previous prime is 15256651651. The next prime is 15256651681. The reversal of 15256651661 is 16615665251.

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., 13168710025 + 2087941636 = 114755^2 + 45694^2 .

It is a cyclic number.

It is not a de Polignac number, because 15256651661 - 2²² = 15252457357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15256651601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7628325830 + 7628325831.

It is an arithmetic number, because the mean of its divisors is an integer number (7628325831).

Almost surely, 2^15256651661 is an apocalyptic number.

It is an amenable number.

15256651661 is a deficient number, since it is larger than the sum of its proper divisors (1).

15256651661 is an equidigital number, since it uses as much as digits as its factorization.

15256651661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 324000, while the sum is 44.

The spelling of 15256651661 in words is "fifteen billion, two hundred fifty-six million, six hundred fifty-one thousand, six hundred sixty-one".