164550721 has 2 divisors, whose sum is σ = 164550722. Its totient is φ = 164550720.

The previous prime is 164550709. The next prime is 164550731. The reversal of 164550721 is 127055461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 126900225 + 37650496 = 11265^2 + 6136^2 .

It is a cyclic number.

It is not a de Polignac number, because 164550721 - 2¹⁷ = 164419649 is a prime.

It is not a weakly prime, because it can be changed into another prime (164550731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82275360 + 82275361.

It is an arithmetic number, because the mean of its divisors is an integer number (82275361).

Almost surely, 2^164550721 is an apocalyptic number.

It is an amenable number.

164550721 is a deficient number, since it is larger than the sum of its proper divisors (1).

164550721 is an equidigital number, since it uses as much as digits as its factorization.

164550721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 164550721 is about 12827.7324964313. The cubic root of 164550721 is about 547.9823828407.

The spelling of 164550721 in words is "one hundred sixty-four million, five hundred fifty thousand, seven hundred twenty-one".