21282231 has 4 divisors (see below), whose sum is σ = 28376312. Its totient is φ = 14188152.

The previous prime is 21282221. The next prime is 21282241. The reversal of 21282231 is 13228212.

It is a happy number.

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 (21282221) and next prime (21282241).

It is not a de Polignac number, because 21282231 - 2⁶ = 21282167 is a prime.

It is a super-2 number, since 2×21282231² = 905866712674722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21282198 and 21282207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21282221) 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, 3547036 + ... + 3547041.

It is an arithmetic number, because the mean of its divisors is an integer number (7094078).

Almost surely, 2^21282231 is an apocalyptic number.

21282231 is a deficient number, since it is larger than the sum of its proper divisors (7094081).

21282231 is an equidigital number, since it uses as much as digits as its factorization.

21282231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7094080.

The product of its digits is 384, while the sum is 21.

The square root of 21282231 is about 4613.2668468234. The cubic root of 21282231 is about 277.1228803121.

The spelling of 21282231 in words is "twenty-one million, two hundred eighty-two thousand, two hundred thirty-one".