21543930 has 48 divisors (see below), whose sum is σ = 59313384. Its totient is φ = 5406720.

The previous prime is 21543923. The next prime is 21543931. The reversal of 21543930 is 3934512.

It can be written as a sum of positive squares in 4 ways, for example, as 21150801 + 393129 = 4599^2 + 627^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21543894 and 21543903.

It is not an unprimeable number, because it can be changed into a prime (21543931) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5511 + ... + 8570.

Almost surely, 2^21543930 is an apocalyptic number.

21543930 is an abundant number, since it is smaller than the sum of its proper divisors (37769454).

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

21543930 is a wasteful number, since it uses less digits than its factorization.

21543930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14111 (or 14108 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 21543930 is about 4641.5439241701. The cubic root of 21543930 is about 278.2541453842.

It can be divided in two parts, 2154 and 3930, that added together give a square (6084 = 78²).

The spelling of 21543930 in words is "twenty-one million, five hundred forty-three thousand, nine hundred thirty".