21023020 has 12 divisors (see below), whose sum is σ = 44148384. Its totient is φ = 8409200.

The previous prime is 21023017. The next prime is 21023047. The reversal of 21023020 is 2032012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21022988 and 21023006.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525556 + ... + 525595.

It is an arithmetic number, because the mean of its divisors is an integer number (3679032).

Almost surely, 2^21023020 is an apocalyptic number.

21023020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21023020 is an abundant number, since it is smaller than the sum of its proper divisors (23125364).

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

21023020 is a wasteful number, since it uses less digits than its factorization.

21023020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1051160 (or 1051158 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 10.

The square root of 21023020 is about 4585.0866949274. The cubic root of 21023020 is about 275.9931910384.

Adding to 21023020 its reverse (2032012), we get a palindrome (23055032).

The spelling of 21023020 in words is "twenty-one million, twenty-three thousand, twenty".