18891920 has 40 divisors (see below), whose sum is σ = 44354304. Its totient is φ = 7482752.

The previous prime is 18891919. The next prime is 18891953. The reversal of 18891920 is 2919881.

It is a tau number, because it is divible by the number of its divisors (40).

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, 7457 + ... + 9663.

Almost surely, 2^18891920 is an apocalyptic number.

18891920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18891920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22177152).

18891920 is an abundant number, since it is smaller than the sum of its proper divisors (25462384).

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

18891920 is a wasteful number, since it uses less digits than its factorization.

18891920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2327 (or 2321 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 18891920 is about 4346.4836362283. The cubic root of 18891920 is about 266.3332360416. Note that the first 3 decimals are identical.

The spelling of 18891920 in words is "eighteen million, eight hundred ninety-one thousand, nine hundred twenty".