165566109501979 has 2 divisors, whose sum is σ = 165566109501980. Its totient is φ = 165566109501978.

The previous prime is 165566109501973. The next prime is 165566109502007. The reversal of 165566109501979 is 979105901665561.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165566109501979 is a prime.

It is a super-2 number, since 2×165566109501979² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (165566109501973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82783054750989 + 82783054750990.

It is an arithmetic number, because the mean of its divisors is an integer number (82783054750990).

Almost surely, 2^{165566109501979} is an apocalyptic number.

165566109501979 is a deficient number, since it is larger than the sum of its proper divisors (1).

165566109501979 is an equidigital number, since it uses as much as digits as its factorization.

165566109501979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 137781000, while the sum is 70.

The spelling of 165566109501979 in words is "one hundred sixty-five trillion, five hundred sixty-six billion, one hundred nine million, five hundred one thousand, nine hundred seventy-nine".