164731561 has 2 divisors, whose sum is σ = 164731562. Its totient is φ = 164731560.

The previous prime is 164731559. The next prime is 164731601. The reversal of 164731561 is 165137461.

164731561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 102637161 + 62094400 = 10131^2 + 7880^2 .

It is a cyclic number.

It is not a de Polignac number, because 164731561 - 2¹ = 164731559 is a prime.

Together with 164731559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (164731531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82365780 + 82365781.

It is an arithmetic number, because the mean of its divisors is an integer number (82365781).

Almost surely, 2^164731561 is an apocalyptic number.

It is an amenable number.

164731561 is a deficient number, since it is larger than the sum of its proper divisors (1).

164731561 is an equidigital number, since it uses as much as digits as its factorization.

164731561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15120, while the sum is 34.

The square root of 164731561 is about 12834.7793514341. The cubic root of 164731561 is about 548.1830521811.

The spelling of 164731561 in words is "one hundred sixty-four million, seven hundred thirty-one thousand, five hundred sixty-one".