21831764 has 12 divisors (see below), whose sum is σ = 38253600. Its totient is φ = 10902168.

The previous prime is 21831701. The next prime is 21831769. The reversal of 21831764 is 46713812.

It is a self number, because there is not a number n which added to its sum of digits gives 21831764.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21831769) 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, 707 + ... + 6645.

It is an arithmetic number, because the mean of its divisors is an integer number (3187800).

Almost surely, 2^21831764 is an apocalyptic number.

It is an amenable number.

21831764 is a deficient number, since it is larger than the sum of its proper divisors (16421836).

21831764 is a wasteful number, since it uses less digits than its factorization.

21831764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6862 (or 6860 counting only the distinct ones).

The product of its digits is 8064, while the sum is 32.

The square root of 21831764 is about 4672.4473244757. The cubic root of 21831764 is about 279.4878563341.

The spelling of 21831764 in words is "twenty-one million, eight hundred thirty-one thousand, seven hundred sixty-four".