21023952 has 80 divisors (see below), whose sum is σ = 57139200. Its totient is φ = 6652800.

The previous prime is 21023941. The next prime is 21023953. The reversal of 21023952 is 25932012.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023953) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 105549 + ... + 105747.

It is an arithmetic number, because the mean of its divisors is an integer number (714240).

Almost surely, 2^21023952 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21023952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28569600).

21023952 is an abundant number, since it is smaller than the sum of its proper divisors (36115248).

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

21023952 is a wasteful number, since it uses less digits than its factorization.

21023952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312 (or 306 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 21023952 is about 4585.1883276481. The cubic root of 21023952 is about 275.9972694542.

Adding to 21023952 its reverse (25932012), we get a palindrome (46955964).

The spelling of 21023952 in words is "twenty-one million, twenty-three thousand, nine hundred fifty-two".