2157665231 has 2 divisors, whose sum is σ = 2157665232. Its totient is φ = 2157665230.

The previous prime is 2157665227. The next prime is 2157665233. The reversal of 2157665231 is 1325667512.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2157665231 - 2² = 2157665227 is a prime.

It is a super-2 number, since 2×2157665231² = 9311038498132566722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 2157665233, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2157665233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078832615 + 1078832616.

It is an arithmetic number, because the mean of its divisors is an integer number (1078832616).

Almost surely, 2^2157665231 is an apocalyptic number.

2157665231 is a deficient number, since it is larger than the sum of its proper divisors (1).

2157665231 is an equidigital number, since it uses as much as digits as its factorization.

2157665231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 75600, while the sum is 38.

The square root of 2157665231 is about 46450.6752480521. The cubic root of 2157665231 is about 1292.1948954281.

The spelling of 2157665231 in words is "two billion, one hundred fifty-seven million, six hundred sixty-five thousand, two hundred thirty-one".