18521840 has 40 divisors (see below), whose sum is σ = 45599760. Its totient is φ = 6972416.

The previous prime is 18521837. The next prime is 18521851. The reversal of 18521840 is 4812581.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5450 + ... + 8169.

It is an arithmetic number, because the mean of its divisors is an integer number (1139994).

Almost surely, 2^18521840 is an apocalyptic number.

18521840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18521840 is an abundant number, since it is smaller than the sum of its proper divisors (27077920).

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

18521840 is a wasteful number, since it uses less digits than its factorization.

18521840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13649 (or 13643 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 29.

The square root of 18521840 is about 4303.7007330901. The cubic root of 18521840 is about 264.5826586187.

The spelling of 18521840 in words is "eighteen million, five hundred twenty-one thousand, eight hundred forty".