21831948 has 18 divisors (see below), whose sum is σ = 55186404. Its totient is φ = 7277304.

The previous prime is 21831941. The next prime is 21831977. The reversal of 21831948 is 84913812.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 606443 = 21831948 / (2 + 1 + 8 + 3 + 1 + 9 + 4 + 8).

It is not an unprimeable number, because it can be changed into a prime (21831941) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 303186 + ... + 303257.

Almost surely, 2^21831948 is an apocalyptic number.

It is an amenable number.

21831948 is an abundant number, since it is smaller than the sum of its proper divisors (33354456).

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

21831948 is a wasteful number, since it uses less digits than its factorization.

21831948 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606453 (or 606448 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 21831948 is about 4672.4670143298. The cubic root of 21831948 is about 279.4886415145.

The spelling of 21831948 in words is "twenty-one million, eight hundred thirty-one thousand, nine hundred forty-eight".