21981333 has 32 divisors (see below), whose sum is σ = 33546240. Its totient is φ = 12680640.

The previous prime is 21981329. The next prime is 21981343. The reversal of 21981333 is 33318912.

It is not a de Polignac number, because 21981333 - 2² = 21981329 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21981333.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21981313) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 98460 + ... + 98682.

It is an arithmetic number, because the mean of its divisors is an integer number (1048320).

Almost surely, 2^21981333 is an apocalyptic number.

It is an amenable number.

21981333 is a deficient number, since it is larger than the sum of its proper divisors (11564907).

21981333 is a wasteful number, since it uses less digits than its factorization.

21981333 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 369.

The product of its digits is 3888, while the sum is 30.

The square root of 21981333 is about 4688.4254286487. The cubic root of 21981333 is about 280.1246596277.

The spelling of 21981333 in words is "twenty-one million, nine hundred eighty-one thousand, three hundred thirty-three".