18397980 has 72 divisors (see below), whose sum is σ = 57129072. Its totient is φ = 4790016.

The previous prime is 18397979. The next prime is 18397993. The reversal of 18397980 is 8979381.

18397980 = T₃₀₀ + T₃₀₁ + ... + T₅₁₅.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6552 + ... + 8928.

Almost surely, 2^18397980 is an apocalyptic number.

18397980 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 18397980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28564536).

18397980 is an abundant number, since it is smaller than the sum of its proper divisors (38731092).

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

18397980 is a wasteful number, since it uses less digits than its factorization.

18397980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2435 (or 2430 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 18397980 is about 4289.2866539787. The cubic root of 18397980 is about 263.9915630913.

The spelling of 18397980 in words is "eighteen million, three hundred ninety-seven thousand, nine hundred eighty".