21423020 has 12 divisors (see below), whose sum is σ = 44988384. Its totient is φ = 8569200.

The previous prime is 21423019. The next prime is 21423053. The reversal of 21423020 is 2032412.

It is a junction number, because it is equal to n+sod(n) for n = 21422986 and 21423004.

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 3 ways as a sum of consecutive naturals, for example, 535556 + ... + 535595.

It is an arithmetic number, because the mean of its divisors is an integer number (3749032).

Almost surely, 2^21423020 is an apocalyptic number.

21423020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21423020 is an abundant number, since it is smaller than the sum of its proper divisors (23565364).

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

21423020 is a wasteful number, since it uses less digits than its factorization.

21423020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1071160 (or 1071158 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 21423020 is about 4628.5008372042. The cubic root of 21423020 is about 277.7326242458.

Adding to 21423020 its reverse (2032412), we get a palindrome (23455432).

The spelling of 21423020 in words is "twenty-one million, four hundred twenty-three thousand, twenty".