21142831 has 2 divisors, whose sum is σ = 21142832. Its totient is φ = 21142830.

The previous prime is 21142829. The next prime is 21142859. The reversal of 21142831 is 13824112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21142831 - 2¹ = 21142829 is a prime.

It is a super-2 number, since 2×21142831² = 894038605389122, which contains 22 as substring.

Together with 21142829, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21142811) 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 as a sum of consecutive naturals, namely, 10571415 + 10571416.

It is an arithmetic number, because the mean of its divisors is an integer number (10571416).

Almost surely, 2^21142831 is an apocalyptic number.

21142831 is a deficient number, since it is larger than the sum of its proper divisors (1).

21142831 is an equidigital number, since it uses as much as digits as its factorization.

21142831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384, while the sum is 22.

The square root of 21142831 is about 4598.1334256413. The cubic root of 21142831 is about 276.5164967861.

Adding to 21142831 its reverse (13824112), we get a palindrome (34966943).

The spelling of 21142831 in words is "twenty-one million, one hundred forty-two thousand, eight hundred thirty-one".