21992180 has 36 divisors (see below), whose sum is σ = 53726148. Its totient is φ = 7539840.

The previous prime is 21992161. The next prime is 21992183. The reversal of 21992180 is 8129912.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 3519376 + 18472804 = 1876^2 + 4298^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21992183) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10241 + ... + 12200.

It is an arithmetic number, because the mean of its divisors is an integer number (1492393).

Almost surely, 2^21992180 is an apocalyptic number.

21992180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21992180 is an abundant number, since it is smaller than the sum of its proper divisors (31733968).

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

21992180 is a wasteful number, since it uses less digits than its factorization.

21992180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22464 (or 22455 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 21992180 is about 4689.5820709313. The cubic root of 21992180 is about 280.1707292105.

The spelling of 21992180 in words is "twenty-one million, nine hundred ninety-two thousand, one hundred eighty".