165551213 has 4 divisors (see below), whose sum is σ = 165587100. Its totient is φ = 165515328.

The previous prime is 165551207. The next prime is 165551257. The reversal of 165551213 is 312155561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 52809289 + 112741924 = 7267^2 + 10618^2 .

It is a cyclic number.

It is not a de Polignac number, because 165551213 - 2¹⁴ = 165534829 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 (165551293) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9788 + ... + 20661.

It is an arithmetic number, because the mean of its divisors is an integer number (41396775).

Almost surely, 2^165551213 is an apocalyptic number.

It is an amenable number.

165551213 is a deficient number, since it is larger than the sum of its proper divisors (35887).

165551213 is an equidigital number, since it uses as much as digits as its factorization.

165551213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35886.

The product of its digits is 4500, while the sum is 29.

The square root of 165551213 is about 12866.6706260788. The cubic root of 165551213 is about 549.0907433809.

The spelling of 165551213 in words is "one hundred sixty-five million, five hundred fifty-one thousand, two hundred thirteen".