165621012 has 24 divisors (see below), whose sum is σ = 390278112. Its totient is φ = 54660000.

The previous prime is 165621011. The next prime is 165621019. The reversal of 165621012 is 210126561.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165621011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67114 + ... + 69537.

It is an arithmetic number, because the mean of its divisors is an integer number (16261588).

Almost surely, 2^165621012 is an apocalyptic number.

165621012 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

165621012 is an abundant number, since it is smaller than the sum of its proper divisors (224657100).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

165621012 is a wasteful number, since it uses less digits than its factorization.

165621012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136759 (or 136757 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 165621012 is about 12869.3827357803. The cubic root of 165621012 is about 549.1679009748.

Adding to 165621012 its reverse (210126561), we get a palindrome (375747573).

The spelling of 165621012 in words is "one hundred sixty-five million, six hundred twenty-one thousand, twelve".