163981957 has 2 divisors, whose sum is σ = 163981958. Its totient is φ = 163981956.

The previous prime is 163981933. The next prime is 163981991. The reversal of 163981957 is 759189361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144744961 + 19236996 = 12031^2 + 4386^2 .

It is a cyclic number.

It is not a de Polignac number, because 163981957 - 2²³ = 155593349 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 163981957.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (163981997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81990978 + 81990979.

It is an arithmetic number, because the mean of its divisors is an integer number (81990979).

Almost surely, 2^163981957 is an apocalyptic number.

It is an amenable number.

163981957 is a deficient number, since it is larger than the sum of its proper divisors (1).

163981957 is an equidigital number, since it uses as much as digits as its factorization.

163981957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 408240, while the sum is 49.

The square root of 163981957 is about 12805.5439946923. The cubic root of 163981957 is about 547.3502931592.

The spelling of 163981957 in words is "one hundred sixty-three million, nine hundred eighty-one thousand, nine hundred fifty-seven".