21343031 has 4 divisors (see below), whose sum is σ = 21352272. Its totient is φ = 21333792.

The previous prime is 21343019. The next prime is 21343039. The reversal of 21343031 is 13034312.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21343031 - 2⁶ = 21342967 is a prime.

It is a super-2 number, since 2×21343031² = 911049944533922, 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 (21343039) 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, 2255 + ... + 6911.

It is an arithmetic number, because the mean of its divisors is an integer number (5338068).

Almost surely, 2^21343031 is an apocalyptic number.

21343031 is a deficient number, since it is larger than the sum of its proper divisors (9241).

21343031 is an equidigital number, since it uses as much as digits as its factorization.

21343031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9240.

The product of its (nonzero) digits is 216, while the sum is 17.

The square root of 21343031 is about 4619.8518374511. The cubic root of 21343031 is about 277.3865282897.

Adding to 21343031 its reverse (13034312), we get a palindrome (34377343).

The spelling of 21343031 in words is "twenty-one million, three hundred forty-three thousand, thirty-one".