18931380 has 72 divisors (see below), whose sum is σ = 57429792. Its totient is φ = 4657536.

The previous prime is 18931379. The next prime is 18931399. The reversal of 18931380 is 8313981.

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, 9207 + ... + 11073.

It is an arithmetic number, because the mean of its divisors is an integer number (797636).

Almost surely, 2^18931380 is an apocalyptic number.

18931380 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 18931380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28714896).

18931380 is an abundant number, since it is smaller than the sum of its proper divisors (38498412).

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

18931380 is a wasteful number, since it uses less digits than its factorization.

18931380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1905 (or 1890 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 18931380 is about 4351.0205699353. The cubic root of 18931380 is about 266.5185392615.

The spelling of 18931380 in words is "eighteen million, nine hundred thirty-one thousand, three hundred eighty".