21843956 has 12 divisors (see below), whose sum is σ = 38462592. Its totient is φ = 10854648.

The previous prime is 21843953. The next prime is 21843979. The reversal of 21843956 is 65934812.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21843953) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16100 + ... + 17403.

It is an arithmetic number, because the mean of its divisors is an integer number (3205216).

Almost surely, 2^21843956 is an apocalyptic number.

It is an amenable number.

21843956 is a deficient number, since it is larger than the sum of its proper divisors (16618636).

21843956 is a wasteful number, since it uses less digits than its factorization.

21843956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33670 (or 33668 counting only the distinct ones).

The product of its digits is 51840, while the sum is 38.

The square root of 21843956 is about 4673.7518119815. The cubic root of 21843956 is about 279.5398735360.

The spelling of 21843956 in words is "twenty-one million, eight hundred forty-three thousand, nine hundred fifty-six".