21820488 has 32 divisors (see below), whose sum is σ = 54908160. Its totient is φ = 7225920.

The previous prime is 21820481. The next prime is 21820489. The reversal of 21820488 is 88402812.

It is a super-2 number, since 2×21820488² = 952267393116288, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21820481) 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 7 ways as a sum of consecutive naturals, for example, 873 + ... + 6663.

It is an arithmetic number, because the mean of its divisors is an integer number (1715880).

Almost surely, 2^21820488 is an apocalyptic number.

It is an amenable number.

21820488 is an abundant number, since it is smaller than the sum of its proper divisors (33087672).

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

21820488 is a wasteful number, since it uses less digits than its factorization.

21820488 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5957 (or 5953 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 33.

The square root of 21820488 is about 4671.2405204613. The cubic root of 21820488 is about 279.4397300077.

It can be divided in two parts, 218 and 20488, that added together give a triangular number (20706 = T₂₀₃).

The spelling of 21820488 in words is "twenty-one million, eight hundred twenty thousand, four hundred eighty-eight".