18981240 has 64 divisors (see below), whose sum is σ = 57231360. Its totient is φ = 5036160.

The previous prime is 18981229. The next prime is 18981307. The reversal of 18981240 is 4218981.

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, 43825 + ... + 44255.

It is an arithmetic number, because the mean of its divisors is an integer number (894240).

Almost surely, 2^18981240 is an apocalyptic number.

18981240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18981240 is an abundant number, since it is smaller than the sum of its proper divisors (38250120).

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

18981240 is a wasteful number, since it uses less digits than its factorization.

18981240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 812 (or 808 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 18981240 is about 4356.7464925102. The cubic root of 18981240 is about 266.7523127676.

The spelling of 18981240 in words is "eighteen million, nine hundred eighty-one thousand, two hundred forty".