18481780 has 24 divisors (see below), whose sum is σ = 39450600. Its totient is φ = 7271040.

The previous prime is 18481769. The next prime is 18481781. The reversal of 18481780 is 8718481.

18481780 = 1103² + 1104² + ... + 1117².

It can be written as a sum of positive squares in 4 ways, for example, as 283024 + 18198756 = 532^2 + 4266^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18481781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6355 + ... + 8794.

It is an arithmetic number, because the mean of its divisors is an integer number (1643775).

Almost surely, 2^18481780 is an apocalyptic number.

18481780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18481780 is an abundant number, since it is smaller than the sum of its proper divisors (20968820).

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

18481780 is a wasteful number, since it uses less digits than its factorization.

18481780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15219 (or 15217 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 37.

The square root of 18481780 is about 4299.0440797926. The cubic root of 18481780 is about 264.3917698808.

The spelling of 18481780 in words is "eighteen million, four hundred eighty-one thousand, seven hundred eighty".