621223165 has 4 divisors (see below), whose sum is σ = 745467804. Its totient is φ = 496978528.

The previous prime is 621223157. The next prime is 621223177. The reversal of 621223165 is 561322126.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 561322126 = 2 ⋅280661063.

It can be written as a sum of positive squares in 2 ways, for example, as 129891609 + 491331556 = 11397^2 + 22166^2 .

It is a cyclic number.

It is not a de Polignac number, because 621223165 - 2³ = 621223157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62122312 + ... + 62122321.

It is an arithmetic number, because the mean of its divisors is an integer number (186366951).

Almost surely, 2^621223165 is an apocalyptic number.

It is an amenable number.

621223165 is a deficient number, since it is larger than the sum of its proper divisors (124244639).

621223165 is a wasteful number, since it uses less digits than its factorization.

621223165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124244638.

The product of its digits is 4320, while the sum is 28.

The square root of 621223165 is about 24924.3488380339. The cubic root of 621223165 is about 853.2622800370.

The spelling of 621223165 in words is "six hundred twenty-one million, two hundred twenty-three thousand, one hundred sixty-five".