18220628 has 12 divisors (see below), whose sum is σ = 31916052. Its totient is φ = 9101760.

The previous prime is 18220621. The next prime is 18220633. The reversal of 18220628 is 82602281.

It can be written as a sum of positive squares in 2 ways, for example, as 4545424 + 13675204 = 2132^2 + 3698^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18220628.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18220621) 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, 6848 + ... + 9128.

It is an arithmetic number, because the mean of its divisors is an integer number (2659671).

Almost surely, 2^18220628 is an apocalyptic number.

It is an amenable number.

18220628 is a deficient number, since it is larger than the sum of its proper divisors (13695424).

18220628 is a wasteful number, since it uses less digits than its factorization.

18220628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4282 (or 4280 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 18220628 is about 4268.5627557762. The cubic root of 18220628 is about 263.1405514549.

The spelling of 18220628 in words is "eighteen million, two hundred twenty thousand, six hundred twenty-eight".