18397880 has 64 divisors (see below), whose sum is σ = 43994880. Its totient is φ = 6912000.

The previous prime is 18397879. The next prime is 18397903. The reversal of 18397880 is 8879381.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45680 + ... + 46080.

It is an arithmetic number, because the mean of its divisors is an integer number (687420).

Almost surely, 2^18397880 is an apocalyptic number.

18397880 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 18397880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21997440).

18397880 is an abundant number, since it is smaller than the sum of its proper divisors (25597000).

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

18397880 is a wasteful number, since it uses less digits than its factorization.

18397880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 480 (or 476 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 44.

The square root of 18397880 is about 4289.2749970129. The cubic root of 18397880 is about 263.9910847923.

The spelling of 18397880 in words is "eighteen million, three hundred ninety-seven thousand, eight hundred eighty".