21431283 has 4 divisors (see below), whose sum is σ = 28575048. Its totient is φ = 14287520.

The previous prime is 21431269. The next prime is 21431303. The reversal of 21431283 is 38213412.

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

It is a cyclic number.

It is not a de Polignac number, because 21431283 - 2⁹ = 21430771 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21431383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3571878 + ... + 3571883.

It is an arithmetic number, because the mean of its divisors is an integer number (7143762).

Almost surely, 2^21431283 is an apocalyptic number.

21431283 is a deficient number, since it is larger than the sum of its proper divisors (7143765).

21431283 is an equidigital number, since it uses as much as digits as its factorization.

21431283 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7143764.

The product of its digits is 1152, while the sum is 24.

The square root of 21431283 is about 4629.3933727865. The cubic root of 21431283 is about 277.7683274237.

Adding to 21431283 its reverse (38213412), we get a palindrome (59644695).

The spelling of 21431283 in words is "twenty-one million, four hundred thirty-one thousand, two hundred eighty-three".