18121240 has 32 divisors (see below), whose sum is σ = 42547680. Its totient is φ = 6932992.

The previous prime is 18121237. The next prime is 18121241. The reversal of 18121240 is 4212181.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18121241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8929 + ... + 10768.

It is an arithmetic number, because the mean of its divisors is an integer number (1329615).

Almost surely, 2^18121240 is an apocalyptic number.

18121240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18121240 is an abundant number, since it is smaller than the sum of its proper divisors (24426440).

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

18121240 is a wasteful number, since it uses less digits than its factorization.

18121240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19731 (or 19727 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 18121240 is about 4256.9049789724. The cubic root of 18121240 is about 262.6612282394.

The spelling of 18121240 in words is "eighteen million, one hundred twenty-one thousand, two hundred forty".