21023420 has 24 divisors (see below), whose sum is σ = 48163248. Its totient is φ = 7644800.

The previous prime is 21023419. The next prime is 21023459. The reversal of 21023420 is 2432012.

It is a junction number, because it is equal to n+sod(n) for n = 21023395 and 21023404.

It is a congruent number.

It is an unprimeable number.

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, 47561 + ... + 48000.

It is an arithmetic number, because the mean of its divisors is an integer number (2006802).

Almost surely, 2^21023420 is an apocalyptic number.

21023420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21023420 is an abundant number, since it is smaller than the sum of its proper divisors (27139828).

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

21023420 is a wasteful number, since it uses less digits than its factorization.

21023420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95581 (or 95579 counting only the distinct ones).

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

The square root of 21023420 is about 4585.1303143967. The cubic root of 21023420 is about 275.9949414462.

Adding to 21023420 its reverse (2432012), we get a palindrome (23455432).

The spelling of 21023420 in words is "twenty-one million, twenty-three thousand, four hundred twenty".