21894231 has 4 divisors (see below), whose sum is σ = 29192312. Its totient is φ = 14596152.

The previous prime is 21894221. The next prime is 21894241. The reversal of 21894231 is 13249812.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21894221) and next prime (21894241).

It is not a de Polignac number, because 21894231 - 2⁶ = 21894167 is a prime.

It is a super-2 number, since 2×21894231² = 958714702162722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21894211) 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, 3649036 + ... + 3649041.

It is an arithmetic number, because the mean of its divisors is an integer number (7298078).

Almost surely, 2^21894231 is an apocalyptic number.

21894231 is a deficient number, since it is larger than the sum of its proper divisors (7298081).

21894231 is an equidigital number, since it uses as much as digits as its factorization.

21894231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7298080.

The product of its digits is 3456, while the sum is 30.

The square root of 21894231 is about 4679.1271621960. The cubic root of 21894231 is about 279.7541677326.

It can be divided in two parts, 218 and 94231, that added together give a palindrome (94449).

The spelling of 21894231 in words is "twenty-one million, eight hundred ninety-four thousand, two hundred thirty-one".