165621947 has 2 divisors, whose sum is σ = 165621948. Its totient is φ = 165621946.

The previous prime is 165621943. The next prime is 165621977. The reversal of 165621947 is 749126561.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 165621947 - 2² = 165621943 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165621941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82810973 + 82810974.

It is an arithmetic number, because the mean of its divisors is an integer number (82810974).

Almost surely, 2^165621947 is an apocalyptic number.

165621947 is a deficient number, since it is larger than the sum of its proper divisors (1).

165621947 is an equidigital number, since it uses as much as digits as its factorization.

165621947 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 41.

The square root of 165621947 is about 12869.4190622576. The cubic root of 165621947 is about 549.1689344005.

The spelling of 165621947 in words is "one hundred sixty-five million, six hundred twenty-one thousand, nine hundred forty-seven".