21943020 has 48 divisors (see below), whose sum is σ = 67027968. Its totient is φ = 5319360.

The previous prime is 21943013. The next prime is 21943021. The reversal of 21943020 is 2034912.

It is a super-2 number, since 2×21943020² = 962992253440800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21943021) 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, 15964 + ... + 17283.

It is an arithmetic number, because the mean of its divisors is an integer number (1396416).

Almost surely, 2^21943020 is an apocalyptic number.

21943020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21943020 is an abundant number, since it is smaller than the sum of its proper divisors (45084948).

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

21943020 is a wasteful number, since it uses less digits than its factorization.

21943020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33270 (or 33268 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 21943020 is about 4684.3377333408. The cubic root of 21943020 is about 279.9618145205.

Adding to 21943020 its reverse (2034912), we get a palindrome (23977932).

The spelling of 21943020 in words is "twenty-one million, nine hundred forty-three thousand, twenty".