18631428 has 12 divisors (see below), whose sum is σ = 43473360. Its totient is φ = 6210472.

The previous prime is 18631423. The next prime is 18631429. The reversal of 18631428 is 82413681.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (18631423) 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, 776298 + ... + 776321.

It is an arithmetic number, because the mean of its divisors is an integer number (3622780).

Almost surely, 2^18631428 is an apocalyptic number.

It is an amenable number.

18631428 is an abundant number, since it is smaller than the sum of its proper divisors (24841932).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18631428 is a wasteful number, since it uses less digits than its factorization.

18631428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1552626 (or 1552624 counting only the distinct ones).

The product of its digits is 9216, while the sum is 33.

The square root of 18631428 is about 4316.4137892468. The cubic root of 18631428 is about 265.1034507690.

The spelling of 18631428 in words is "eighteen million, six hundred thirty-one thousand, four hundred twenty-eight".