157561 has 2 divisors, whose sum is σ = 157562. Its totient is φ = 157560.

The previous prime is 157559. The next prime is 157571. The reversal of 157561 is 165751.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133225 + 24336 = 365^2 + 156^2 .

It is a cyclic number.

It is not a de Polignac number, because 157561 - 2¹ = 157559 is a prime.

Together with 157559, it forms a pair of twin primes.

It is equal to p₁₄₄₈₈ and since 157561 and 14488 have the same sum of digits, it is a Honaker prime.

It is a plaindrome in base 16.

It is a nialpdrome in base 12.

It is not a weakly prime, because it can be changed into another prime (157571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78780 + 78781.

It is an arithmetic number, because the mean of its divisors is an integer number (78781).

2¹⁵⁷⁵⁶¹ is an apocalyptic number.

It is an amenable number.

157561 is a deficient number, since it is larger than the sum of its proper divisors (1).

157561 is an equidigital number, since it uses as much as digits as its factorization.

157561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1050, while the sum is 25.

The square root of 157561 is about 396.9395419960. The cubic root of 157561 is about 54.0110859727.

The spelling of 157561 in words is "one hundred fifty-seven thousand, five hundred sixty-one".