213111431 has 4 divisors (see below), whose sum is σ = 229504632. Its totient is φ = 196718232.

The previous prime is 213111421. The next prime is 213111433. The reversal of 213111431 is 134111312.

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

It is a cyclic number.

It is not a de Polignac number, because 213111431 - 2²² = 208917127 is a prime.

It is a super-2 number, since 2×213111431² = 90832964045735522, 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 (213111433) 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, 8196581 + ... + 8196606.

It is an arithmetic number, because the mean of its divisors is an integer number (57376158).

Almost surely, 2^213111431 is an apocalyptic number.

213111431 is a deficient number, since it is larger than the sum of its proper divisors (16393201).

213111431 is a wasteful number, since it uses less digits than its factorization.

213111431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16393200.

The product of its digits is 72, while the sum is 17.

The square root of 213111431 is about 14598.3365833235. The cubic root of 213111431 is about 597.3133872156.

Adding to 213111431 its reverse (134111312), we get a palindrome (347222743).

The spelling of 213111431 in words is "two hundred thirteen million, one hundred eleven thousand, four hundred thirty-one".