157901981 has 2 divisors, whose sum is σ = 157901982. Its totient is φ = 157901980.

The previous prime is 157901971. The next prime is 157902053. The reversal of 157901981 is 189109751.

157901981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 156025081 + 1876900 = 12491^2 + 1370^2 .

It is a cyclic number.

It is not a de Polignac number, because 157901981 - 2⁶ = 157901917 is a prime.

It is a super-2 number, since 2×157901981² = 49866071207448722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (157901921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78950990 + 78950991.

It is an arithmetic number, because the mean of its divisors is an integer number (78950991).

Almost surely, 2^157901981 is an apocalyptic number.

It is an amenable number.

157901981 is a deficient number, since it is larger than the sum of its proper divisors (1).

157901981 is an equidigital number, since it uses as much as digits as its factorization.

157901981 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 157901981 is about 12565.9054986101. The cubic root of 157901981 is about 540.5002006741.

It can be divided in two parts, 15790 and 1981, that added together give a palindrome (17771).

The spelling of 157901981 in words is "one hundred fifty-seven million, nine hundred one thousand, nine hundred eighty-one".