18212728 has 8 divisors (see below), whose sum is σ = 34148880. Its totient is φ = 9106360.

The previous prime is 18212683. The next prime is 18212731. The reversal of 18212728 is 82721281.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×18212728² = 663406922403968, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18212728.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1138288 + ... + 1138303.

It is an arithmetic number, because the mean of its divisors is an integer number (4268610).

Almost surely, 2^18212728 is an apocalyptic number.

It is an amenable number.

18212728 is a deficient number, since it is larger than the sum of its proper divisors (15936152).

18212728 is a wasteful number, since it uses less digits than its factorization.

18212728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2276597 (or 2276593 counting only the distinct ones).

The product of its digits is 3584, while the sum is 31.

The square root of 18212728 is about 4267.6372854309. The cubic root of 18212728 is about 263.1025156114.

The spelling of 18212728 in words is "eighteen million, two hundred twelve thousand, seven hundred twenty-eight".