18681630 has 32 divisors (see below), whose sum is σ = 48912768. Its totient is φ = 4528800.

The previous prime is 18681613. The next prime is 18681643. The reversal of 18681630 is 3618681.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 18681591 and 18681600.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27976 + ... + 28635.

It is an arithmetic number, because the mean of its divisors is an integer number (1528524).

Almost surely, 2^18681630 is an apocalyptic number.

18681630 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18681630 is an abundant number, since it is smaller than the sum of its proper divisors (30231138).

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

18681630 is a wasteful number, since it uses less digits than its factorization.

18681630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56632.

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 18681630 is about 4322.2251213929. The cubic root of 18681630 is about 265.3413424993.

The spelling of 18681630 in words is "eighteen million, six hundred eighty-one thousand, six hundred thirty".