21930540 has 24 divisors (see below), whose sum is σ = 61405680. Its totient is φ = 5848128.

The previous prime is 21930511. The next prime is 21930553. The reversal of 21930540 is 4503912.

It is a self number, because there is not a number n which added to its sum of digits gives 21930540.

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, 182695 + ... + 182814.

It is an arithmetic number, because the mean of its divisors is an integer number (2558570).

Almost surely, 2^21930540 is an apocalyptic number.

21930540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21930540 is an abundant number, since it is smaller than the sum of its proper divisors (39475140).

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

21930540 is a wasteful number, since it uses less digits than its factorization.

21930540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 365521 (or 365519 counting only the distinct ones).

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

The square root of 21930540 is about 4683.0054452243. The cubic root of 21930540 is about 279.9087287551.

The spelling of 21930540 in words is "twenty-one million, nine hundred thirty thousand, five hundred forty".