21889231 has 16 divisors (see below), whose sum is σ = 27496000. Its totient is φ = 17315424.

The previous prime is 21889223. The next prime is 21889247. The reversal of 21889231 is 13298812.

It is not a de Polignac number, because 21889231 - 2³ = 21889223 is a prime.

It is a super-2 number, since 2×21889231² = 958276867542722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21880231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2005 + ... + 6913.

It is an arithmetic number, because the mean of its divisors is an integer number (1718500).

Almost surely, 2^21889231 is an apocalyptic number.

21889231 is a deficient number, since it is larger than the sum of its proper divisors (5606769).

21889231 is an equidigital number, since it uses as much as digits as its factorization.

21889231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4943 (or 4929 counting only the distinct ones).

The product of its digits is 6912, while the sum is 34.

The square root of 21889231 is about 4678.5928440077. The cubic root of 21889231 is about 279.7328702299.

The spelling of 21889231 in words is "twenty-one million, eight hundred eighty-nine thousand, two hundred thirty-one".