21873291 has 12 divisors (see below), whose sum is σ = 32057256. Its totient is φ = 13256320.

The previous prime is 21873277. The next prime is 21873311. The reversal of 21873291 is 19237812.

It is not a de Polignac number, because 21873291 - 2⁹ = 21872779 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21873251) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29766 + ... + 30491.

It is an arithmetic number, because the mean of its divisors is an integer number (2671438).

Almost surely, 2^21873291 is an apocalyptic number.

21873291 is a deficient number, since it is larger than the sum of its proper divisors (10183965).

21873291 is a wasteful number, since it uses less digits than its factorization.

21873291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60282 (or 60271 counting only the distinct ones).

The product of its digits is 6048, while the sum is 33.

The square root of 21873291 is about 4676.8890301139. The cubic root of 21873291 is about 279.6649521330.

The spelling of 21873291 in words is "twenty-one million, eight hundred seventy-three thousand, two hundred ninety-one".