161931311 has 2 divisors, whose sum is σ = 161931312. Its totient is φ = 161931310.

The previous prime is 161931283. The next prime is 161931313. The reversal of 161931311 is 113139161.

161931311 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 is a cyclic number.

It is not a de Polignac number, because 161931311 - 2¹⁴ = 161914927 is a prime.

Together with 161931313, 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 (161931313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80965655 + 80965656.

It is an arithmetic number, because the mean of its divisors is an integer number (80965656).

Almost surely, 2^161931311 is an apocalyptic number.

161931311 is a deficient number, since it is larger than the sum of its proper divisors (1).

161931311 is an equidigital number, since it uses as much as digits as its factorization.

161931311 is an evil number, because the sum of its binary digits is even.

The product of its digits is 486, while the sum is 26.

The square root of 161931311 is about 12725.2234165063. The cubic root of 161931311 is about 545.0591199228.

The spelling of 161931311 in words is "one hundred sixty-one million, nine hundred thirty-one thousand, three hundred eleven".