157181561 has 2 divisors, whose sum is σ = 157181562. Its totient is φ = 157181560.

The previous prime is 157181551. The next prime is 157181593. The reversal of 157181561 is 165181751.

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., 134676025 + 22505536 = 11605^2 + 4744^2 .

It is a cyclic number.

It is not a de Polignac number, because 157181561 - 2¹⁰ = 157180537 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (157181551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78590780 + 78590781.

It is an arithmetic number, because the mean of its divisors is an integer number (78590781).

Almost surely, 2^157181561 is an apocalyptic number.

It is an amenable number.

157181561 is a deficient number, since it is larger than the sum of its proper divisors (1).

157181561 is an equidigital number, since it uses as much as digits as its factorization.

157181561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8400, while the sum is 35.

The square root of 157181561 is about 12537.2070653715. The cubic root of 157181561 is about 539.6769455461.

The spelling of 157181561 in words is "one hundred fifty-seven million, one hundred eighty-one thousand, five hundred sixty-one".