165164212421 has 16 divisors (see below), whose sum is σ = 183840054384. Its totient is φ = 147393851904.

The previous prime is 165164212417. The next prime is 165164212457. The reversal of 165164212421 is 124212461561.

It can be written as a sum of positive squares in 8 ways, for example, as 4652604100 + 160511608321 = 68210^2 + 400639^2 .

It is not a de Polignac number, because 165164212421 - 2² = 165164212417 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165164212321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1018040 + ... + 1169073.

It is an arithmetic number, because the mean of its divisors is an integer number (11490003399).

Almost surely, 2^165164212421 is an apocalyptic number.

It is an amenable number.

165164212421 is a deficient number, since it is larger than the sum of its proper divisors (18675841963).

165164212421 is a wasteful number, since it uses less digits than its factorization.

165164212421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2187320.

The product of its digits is 23040, while the sum is 35.

Adding to 165164212421 its reverse (124212461561), we get a palindrome (289376673982).

The spelling of 165164212421 in words is "one hundred sixty-five billion, one hundred sixty-four million, two hundred twelve thousand, four hundred twenty-one".