21543412 has 24 divisors (see below), whose sum is σ = 41261472. Its totient is φ = 9760800.

The previous prime is 21543407. The next prime is 21543439. The reversal of 21543412 is 21434512.

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17943 + ... + 19105.

It is an arithmetic number, because the mean of its divisors is an integer number (1719228).

Almost surely, 2^21543412 is an apocalyptic number.

21543412 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21543412 is a deficient number, since it is larger than the sum of its proper divisors (19718060).

21543412 is a wasteful number, since it uses less digits than its factorization.

21543412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1599 (or 1597 counting only the distinct ones).

The product of its digits is 960, while the sum is 22.

The square root of 21543412 is about 4641.4881234363. The cubic root of 21543412 is about 278.2519152618.

Adding to 21543412 its reverse (21434512), we get a palindrome (42977924).

Subtracting from 21543412 its reverse (21434512), we obtain a square (108900 = 330²).

The spelling of 21543412 in words is "twenty-one million, five hundred forty-three thousand, four hundred twelve".