21831330 has 16 divisors (see below), whose sum is σ = 52395264. Its totient is φ = 5821680.

The previous prime is 21831263. The next prime is 21831353. The reversal of 21831330 is 3313812.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21831297 and 21831306.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 363826 + ... + 363885.

It is an arithmetic number, because the mean of its divisors is an integer number (3274704).

Almost surely, 2^21831330 is an apocalyptic number.

21831330 is an abundant number, since it is smaller than the sum of its proper divisors (30563934).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21831330 is a wasteful number, since it uses less digits than its factorization.

21831330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 727721.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 21831330 is about 4672.4008817737. The cubic root of 21831330 is about 279.4860043150.

The spelling of 21831330 in words is "twenty-one million, eight hundred thirty-one thousand, three hundred thirty".