21499880 has 16 divisors (see below), whose sum is σ = 48374820. Its totient is φ = 8599936.

The previous prime is 21499879. The next prime is 21499889. The reversal of 21499880 is 8899412.

It can be written as a sum of positive squares in 2 ways, for example, as 20232004 + 1267876 = 4498^2 + 1126^2 .

It is not an unprimeable number, because it can be changed into a prime (21499889) 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 3 ways as a sum of consecutive naturals, for example, 268709 + ... + 268788.

Almost surely, 2^21499880 is an apocalyptic number.

21499880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21499880 is an abundant number, since it is smaller than the sum of its proper divisors (26874940).

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

21499880 is a wasteful number, since it uses less digits than its factorization.

21499880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 537508 (or 537504 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 21499880 is about 4636.7963077970. The cubic root of 21499880 is about 278.0643709951.

The spelling of 21499880 in words is "twenty-one million, four hundred ninety-nine thousand, eight hundred eighty".