18629221 has 4 divisors (see below), whose sum is σ = 20062252. Its totient is φ = 17196192.

The previous prime is 18629207. The next prime is 18629231. The reversal of 18629221 is 12292681.

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 12152196 + 6477025 = 3486^2 + 2545^2 .

It is not a de Polignac number, because 18629221 - 2⁵ = 18629189 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 (18629231) 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, 716496 + ... + 716521.

It is an arithmetic number, because the mean of its divisors is an integer number (5015563).

Almost surely, 2^18629221 is an apocalyptic number.

It is an amenable number.

18629221 is a deficient number, since it is larger than the sum of its proper divisors (1433031).

18629221 is a wasteful number, since it uses less digits than its factorization.

18629221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1433030.

The product of its digits is 3456, while the sum is 31.

The square root of 18629221 is about 4316.1581296333. The cubic root of 18629221 is about 265.0929826785.

The spelling of 18629221 in words is "eighteen million, six hundred twenty-nine thousand, two hundred twenty-one".