21260180 has 12 divisors (see below), whose sum is σ = 44646420. Its totient is φ = 8504064.

The previous prime is 21260177. The next prime is 21260191. The reversal of 21260180 is 8106212.

It can be written as a sum of positive squares in 2 ways, for example, as 6728836 + 14531344 = 2594^2 + 3812^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1063009 = 21260180 / (2 + 1 + 2 + 6 + 0 + 1 + 8 + 0).

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 531485 + ... + 531524.

It is an arithmetic number, because the mean of its divisors is an integer number (3720535).

Almost surely, 2^21260180 is an apocalyptic number.

21260180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21260180 is an abundant number, since it is smaller than the sum of its proper divisors (23386240).

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

21260180 is a wasteful number, since it uses less digits than its factorization.

21260180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1063018 (or 1063016 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 21260180 is about 4610.8762724671. The cubic root of 21260180 is about 277.0271361461.

Adding to 21260180 its reverse (8106212), we get a palindrome (29366392).

The spelling of 21260180 in words is "twenty-one million, two hundred sixty thousand, one hundred eighty".