21965889 has 8 divisors (see below), whose sum is σ = 31950432. Its totient is φ = 13312640.

The previous prime is 21965863. The next prime is 21965893. The reversal of 21965889 is 98856912.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21965889 - 2⁷ = 21965761 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21965899) by changing a digit.

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, 332784 + ... + 332849.

It is an arithmetic number, because the mean of its divisors is an integer number (3993804).

Almost surely, 2^21965889 is an apocalyptic number.

It is an amenable number.

21965889 is a deficient number, since it is larger than the sum of its proper divisors (9984543).

21965889 is a wasteful number, since it uses less digits than its factorization.

21965889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665647.

The product of its digits is 311040, while the sum is 48.

The square root of 21965889 is about 4686.7781044125. The cubic root of 21965889 is about 280.0590394211.

The spelling of 21965889 in words is "twenty-one million, nine hundred sixty-five thousand, eight hundred eighty-nine".