18251920 has 40 divisors (see below), whose sum is σ = 42624504. Its totient is φ = 7268352.

The previous prime is 18251911. The next prime is 18251921. The reversal of 18251920 is 2915281.

It can be written as a sum of positive squares in 4 ways, for example, as 5089536 + 13162384 = 2256^2 + 3628^2 .

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

It is not an unprimeable number, because it can be changed into a prime (18251921) 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, 26622 + ... + 27298.

Almost surely, 2^18251920 is an apocalyptic number.

18251920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18251920 is an abundant number, since it is smaller than the sum of its proper divisors (24372584).

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

18251920 is a wasteful number, since it uses less digits than its factorization.

18251920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1027 (or 1021 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 18251920 is about 4272.2265857513. The cubic root of 18251920 is about 263.2911039833.

The spelling of 18251920 in words is "eighteen million, two hundred fifty-one thousand, nine hundred twenty".