18891690 has 16 divisors (see below), whose sum is σ = 45340128. Its totient is φ = 5037776.

The previous prime is 18891689. The next prime is 18891701. The reversal of 18891690 is 9619881.

It is a super-2 number, since 2×18891690² = 713791902112200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 314832 + ... + 314891.

It is an arithmetic number, because the mean of its divisors is an integer number (2833758).

Almost surely, 2^18891690 is an apocalyptic number.

18891690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18891690 is an abundant number, since it is smaller than the sum of its proper divisors (26448438).

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

18891690 is a wasteful number, since it uses less digits than its factorization.

18891690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 629733.

The product of its (nonzero) digits is 31104, while the sum is 42.

The square root of 18891690 is about 4346.4571779784. The cubic root of 18891690 is about 266.3321552111.

The spelling of 18891690 in words is "eighteen million, eight hundred ninety-one thousand, six hundred ninety".