21472820 has 24 divisors (see below), whose sum is σ = 45196704. Its totient is φ = 8569376.

The previous prime is 21472817. The next prime is 21472849. The reversal of 21472820 is 2827412.

It is a super-2 number, since 2×21472820² = 922163997504800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21472820.

It is a congruent number.

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, 10307 + ... + 12213.

It is an arithmetic number, because the mean of its divisors is an integer number (1883196).

Almost surely, 2^21472820 is an apocalyptic number.

21472820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21472820 is an abundant number, since it is smaller than the sum of its proper divisors (23723884).

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

21472820 is a wasteful number, since it uses less digits than its factorization.

21472820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2479 (or 2477 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 21472820 is about 4633.8774260871. The cubic root of 21472820 is about 277.9476636636.

The spelling of 21472820 in words is "twenty-one million, four hundred seventy-two thousand, eight hundred twenty".