21831889 has 4 divisors (see below), whose sum is σ = 21902400. Its totient is φ = 21761380.

The previous prime is 21831881. The next prime is 21831911. The reversal of 21831889 is 98813812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21831889 - 2³ = 21831881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21831881) 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, 34789 + ... + 35410.

It is an arithmetic number, because the mean of its divisors is an integer number (5475600).

Almost surely, 2^21831889 is an apocalyptic number.

It is an amenable number.

21831889 is a deficient number, since it is larger than the sum of its proper divisors (70511).

21831889 is an equidigital number, since it uses as much as digits as its factorization.

21831889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70510.

The product of its digits is 27648, while the sum is 40.

The square root of 21831889 is about 4672.4607007443. The cubic root of 21831889 is about 279.4883897452.

The spelling of 21831889 in words is "twenty-one million, eight hundred thirty-one thousand, eight hundred eighty-nine".