21802420 has 24 divisors (see below), whose sum is σ = 46368000. Its totient is φ = 8609952.

The previous prime is 21802411. The next prime is 21802439. The reversal of 21802420 is 2420812.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5320 + ... + 8479.

It is an arithmetic number, because the mean of its divisors is an integer number (1932000).

Almost surely, 2^21802420 is an apocalyptic number.

21802420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21802420 is an abundant number, since it is smaller than the sum of its proper divisors (24565580).

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

21802420 is a wasteful number, since it uses less digits than its factorization.

21802420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13887 (or 13885 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 21802420 is about 4669.3061583066. The cubic root of 21802420 is about 279.3625806296.

It can be divided in two parts, 21802 and 420, that added together give a palindrome (22222).

The spelling of 21802420 in words is "twenty-one million, eight hundred two thousand, four hundred twenty".