213123431 has 4 divisors (see below), whose sum is σ = 213260664. Its totient is φ = 212986200.

The previous prime is 213123401. The next prime is 213123439. The reversal of 213123431 is 134321312.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213123431 is a prime.

It is a super-2 number, since 2×213123431² = 90843193682423522, 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 (213123439) 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, 66260 + ... + 69401.

It is an arithmetic number, because the mean of its divisors is an integer number (53315166).

Almost surely, 2^213123431 is an apocalyptic number.

213123431 is a deficient number, since it is larger than the sum of its proper divisors (137233).

213123431 is a wasteful number, since it uses less digits than its factorization.

213123431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137232.

The product of its digits is 432, while the sum is 20.

The square root of 213123431 is about 14598.7475832689. The cubic root of 213123431 is about 597.3245982928.

Adding to 213123431 its reverse (134321312), we get a palindrome (347444743).

The spelling of 213123431 in words is "two hundred thirteen million, one hundred twenty-three thousand, four hundred thirty-one".