165621121069 has 2 divisors, whose sum is σ = 165621121070. Its totient is φ = 165621121068.

The previous prime is 165621121049. The next prime is 165621121103. The reversal of 165621121069 is 960121126561.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 150533912169 + 15087208900 = 387987^2 + 122830^2 .

It is a cyclic number.

It is not a de Polignac number, because 165621121069 - 2²¹ = 165619023917 is a prime.

It is a super-2 number, since 2×165621121069² (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 (165621121009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82810560534 + 82810560535.

It is an arithmetic number, because the mean of its divisors is an integer number (82810560535).

Almost surely, 2^165621121069 is an apocalyptic number.

It is an amenable number.

165621121069 is a deficient number, since it is larger than the sum of its proper divisors (1).

165621121069 is an equidigital number, since it uses as much as digits as its factorization.

165621121069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38880, while the sum is 40.

The spelling of 165621121069 in words is "one hundred sixty-five billion, six hundred twenty-one million, one hundred twenty-one thousand, sixty-nine".