21343131 has 6 divisors (see below), whose sum is σ = 30828980. Its totient is φ = 14228748.

The previous prime is 21343129. The next prime is 21343139. The reversal of 21343131 is 13134312.

It is not a de Polignac number, because 21343131 - 2¹ = 21343129 is a prime.

It is a super-2 number, since 2×21343131² = 911058481766322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21343139) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1185721 + ... + 1185738.

Almost surely, 2^21343131 is an apocalyptic number.

21343131 is a deficient number, since it is larger than the sum of its proper divisors (9485849).

21343131 is a wasteful number, since it uses less digits than its factorization.

21343131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2371465 (or 2371462 counting only the distinct ones).

The product of its digits is 216, while the sum is 18.

The square root of 21343131 is about 4619.8626602963. The cubic root of 21343131 is about 277.3869615086.

Adding to 21343131 its reverse (13134312), we get a palindrome (34477443).

The spelling of 21343131 in words is "twenty-one million, three hundred forty-three thousand, one hundred thirty-one".