164193991 has 24 divisors (see below), whose sum is σ = 190103760. Its totient is φ = 140914944.

The previous prime is 164193979. The next prime is 164194013. The reversal of 164193991 is 199391461.

It is not a de Polignac number, because 164193991 - 2¹⁵ = 164161223 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164193091) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 276591 + ... + 277183.

It is an arithmetic number, because the mean of its divisors is an integer number (7920990).

Almost surely, 2^164193991 is an apocalyptic number.

164193991 is a deficient number, since it is larger than the sum of its proper divisors (25909769).

164193991 is a wasteful number, since it uses less digits than its factorization.

164193991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 703 (or 684 counting only the distinct ones).

The product of its digits is 52488, while the sum is 43.

The square root of 164193991 is about 12813.8203124595. The cubic root of 164193991 is about 547.5861054569.

The spelling of 164193991 in words is "one hundred sixty-four million, one hundred ninety-three thousand, nine hundred ninety-one".