165456315991 has 2 divisors, whose sum is σ = 165456315992. Its totient is φ = 165456315990.

The previous prime is 165456315989. The next prime is 165456316057. The reversal of 165456315991 is 199513654561.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 165456315991 - 2¹ = 165456315989 is a prime.

Together with 165456315989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165456315901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82728157995 + 82728157996.

It is an arithmetic number, because the mean of its divisors is an integer number (82728157996).

Almost surely, 2^165456315991 is an apocalyptic number.

165456315991 is a deficient number, since it is larger than the sum of its proper divisors (1).

165456315991 is an equidigital number, since it uses as much as digits as its factorization.

165456315991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4374000, while the sum is 55.

The spelling of 165456315991 in words is "one hundred sixty-five billion, four hundred fifty-six million, three hundred fifteen thousand, nine hundred ninety-one".