21249180 has 36 divisors (see below), whose sum is σ = 64456392. Its totient is φ = 5666400.

The previous prime is 21249161. The next prime is 21249191. The reversal of 21249180 is 8194212.

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

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 11 ways as a sum of consecutive naturals, for example, 58846 + ... + 59205.

Almost surely, 2^21249180 is an apocalyptic number.

21249180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21249180 is an abundant number, since it is smaller than the sum of its proper divisors (43207212).

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

21249180 is a wasteful number, since it uses less digits than its factorization.

21249180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118066 (or 118061 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 21249180 is about 4609.6832863007. The cubic root of 21249180 is about 276.9793500313.

The spelling of 21249180 in words is "twenty-one million, two hundred forty-nine thousand, one hundred eighty".