164031991 has 2 divisors, whose sum is σ = 164031992. Its totient is φ = 164031990.

The previous prime is 164031983. The next prime is 164032009. The reversal of 164031991 is 199130461.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 164031991 - 2³ = 164031983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (164031961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82015995 + 82015996.

It is an arithmetic number, because the mean of its divisors is an integer number (82015996).

Almost surely, 2^164031991 is an apocalyptic number.

164031991 is a deficient number, since it is larger than the sum of its proper divisors (1).

164031991 is an equidigital number, since it uses as much as digits as its factorization.

164031991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 164031991 is about 12807.4974526642. The cubic root of 164031991 is about 547.4059564777.

The spelling of 164031991 in words is "one hundred sixty-four million, thirty-one thousand, nine hundred ninety-one".