165427856981 has 2 divisors, whose sum is σ = 165427856982. Its totient is φ = 165427856980.

The previous prime is 165427856927. The next prime is 165427856999. The reversal of 165427856981 is 189658724561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 100279888900 + 65147968081 = 316670^2 + 255241^2 .

It is an emirp because it is prime and its reverse (189658724561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 165427856981 - 2¹⁴ = 165427840597 is a prime.

It is a super-2 number, since 2×165427856981² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165427876981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82713928490 + 82713928491.

It is an arithmetic number, because the mean of its divisors is an integer number (82713928491).

Almost surely, 2^165427856981 is an apocalyptic number.

It is an amenable number.

165427856981 is a deficient number, since it is larger than the sum of its proper divisors (1).

165427856981 is an equidigital number, since it uses as much as digits as its factorization.

165427856981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29030400, while the sum is 62.

The spelling of 165427856981 in words is "one hundred sixty-five billion, four hundred twenty-seven million, eight hundred fifty-six thousand, nine hundred eighty-one".