157910981 has 2 divisors, whose sum is σ = 157910982. Its totient is φ = 157910980.

The previous prime is 157910953. The next prime is 157910989. The reversal of 157910981 is 189019751.

157910981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 108784900 + 49126081 = 10430^2 + 7009^2 .

It is an emirp because it is prime and its reverse (189019751) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 157910981 - 2²² = 153716677 is a prime.

It is a super-2 number, since 2×157910981² = 49871755840764722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (157910989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78955490 + 78955491.

It is an arithmetic number, because the mean of its divisors is an integer number (78955491).

Almost surely, 2^157910981 is an apocalyptic number.

It is an amenable number.

157910981 is a deficient number, since it is larger than the sum of its proper divisors (1).

157910981 is an equidigital number, since it uses as much as digits as its factorization.

157910981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22680, while the sum is 41.

The square root of 157910981 is about 12566.2636053841. The cubic root of 157910981 is about 540.5104695117.

It can be divided in two parts, 15 and 7910981, that multiplied together give a triangular number (118664715 = T₁₅₄₀₅).

The spelling of 157910981 in words is "one hundred fifty-seven million, nine hundred ten thousand, nine hundred eighty-one".