213531431 has 2 divisors, whose sum is σ = 213531432. Its totient is φ = 213531430.

The previous prime is 213531419. The next prime is 213531457. The reversal of 213531431 is 134135312.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213531431 is a prime.

It is a super-2 number, since 2×213531431² = 91191344049815522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 213531397 and 213531406.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213531631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106765715 + 106765716.

It is an arithmetic number, because the mean of its divisors is an integer number (106765716).

Almost surely, 2^213531431 is an apocalyptic number.

213531431 is a deficient number, since it is larger than the sum of its proper divisors (1).

213531431 is an equidigital number, since it uses as much as digits as its factorization.

213531431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 23.

The square root of 213531431 is about 14612.7147032986. The cubic root of 213531431 is about 597.7055247869.

Adding to 213531431 its reverse (134135312), we get a palindrome (347666743).

The spelling of 213531431 in words is "two hundred thirteen million, five hundred thirty-one thousand, four hundred thirty-one".