21682420 has 24 divisors (see below), whose sum is σ = 47930400. Its totient is φ = 8216352.

The previous prime is 21682417. The next prime is 21682433. The reversal of 21682420 is 2428612.

It is a happy number.

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, 28150 + ... + 28909.

It is an arithmetic number, because the mean of its divisors is an integer number (1997100).

Almost surely, 2^21682420 is an apocalyptic number.

21682420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21682420 is an abundant number, since it is smaller than the sum of its proper divisors (26247980).

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

21682420 is a wasteful number, since it uses less digits than its factorization.

21682420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57087 (or 57085 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 21682420 is about 4656.4385532293. The cubic root of 21682420 is about 278.8491024219.

The spelling of 21682420 in words is "twenty-one million, six hundred eighty-two thousand, four hundred twenty".