164942809 has 2 divisors, whose sum is σ = 164942810. Its totient is φ = 164942808.

The previous prime is 164942803. The next prime is 164942831. The reversal of 164942809 is 908249461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 148718025 + 16224784 = 12195^2 + 4028^2 .

It is a cyclic number.

It is not a de Polignac number, because 164942809 - 2⁷ = 164942681 is a prime.

It is a super-2 number, since 2×164942809² = 54412260481620962, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (164942803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82471404 + 82471405.

It is an arithmetic number, because the mean of its divisors is an integer number (82471405).

Almost surely, 2^164942809 is an apocalyptic number.

It is an amenable number.

164942809 is a deficient number, since it is larger than the sum of its proper divisors (1).

164942809 is an equidigital number, since it uses as much as digits as its factorization.

164942809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 43.

The square root of 164942809 is about 12843.0062290727. The cubic root of 164942809 is about 548.4172779058.

The spelling of 164942809 in words is "one hundred sixty-four million, nine hundred forty-two thousand, eight hundred nine".