253981991 has 2 divisors, whose sum is σ = 253981992. Its totient is φ = 253981990.

The previous prime is 253981969. The next prime is 253982009. The reversal of 253981991 is 199189352.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 253981991 - 2²² = 249787687 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (253981291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 126990995 + 126990996.

It is an arithmetic number, because the mean of its divisors is an integer number (126990996).

Almost surely, 2^253981991 is an apocalyptic number.

253981991 is a deficient number, since it is larger than the sum of its proper divisors (1).

253981991 is an equidigital number, since it uses as much as digits as its factorization.

253981991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 174960, while the sum is 47.

The square root of 253981991 is about 15936.8124479144. The cubic root of 253981991 is about 633.2875853998.

The spelling of 253981991 in words is "two hundred fifty-three million, nine hundred eighty-one thousand, nine hundred ninety-one".