21498820 has 24 divisors (see below), whose sum is σ = 51597504. Its totient is φ = 7370976.

The previous prime is 21498817. The next prime is 21498847. The reversal of 21498820 is 2889412.

It is a super-2 number, since 2×21498820² = 924398522784800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76642 + ... + 76921.

It is an arithmetic number, because the mean of its divisors is an integer number (2149896).

Almost surely, 2^21498820 is an apocalyptic number.

21498820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21498820 is an abundant number, since it is smaller than the sum of its proper divisors (30098684).

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

21498820 is a wasteful number, since it uses less digits than its factorization.

21498820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153579 (or 153577 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 21498820 is about 4636.6820033295. The cubic root of 21498820 is about 278.0598011544.

The spelling of 21498820 in words is "twenty-one million, four hundred ninety-eight thousand, eight hundred twenty".