18972180 has 36 divisors (see below), whose sum is σ = 57549492. Its totient is φ = 5059200.

The previous prime is 18972179. The next prime is 18972181. The reversal of 18972180 is 8127981.

It is an interprime number because it is at equal distance from previous prime (18972179) and next prime (18972181).

It can be written as a sum of positive squares in 2 ways, for example, as 2178576 + 16793604 = 1476^2 + 4098^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×18972180² = 719887227904800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18972181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 52521 + ... + 52880.

It is an arithmetic number, because the mean of its divisors is an integer number (1598597).

Almost surely, 2^18972180 is an apocalyptic number.

18972180 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18972180 is an abundant number, since it is smaller than the sum of its proper divisors (38577312).

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

18972180 is a wasteful number, since it uses less digits than its factorization.

18972180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105416 (or 105411 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 18972180 is about 4355.7066016893. The cubic root of 18972180 is about 266.7098645297.

The spelling of 18972180 in words is "eighteen million, nine hundred seventy-two thousand, one hundred eighty".