213021431 has 4 divisors (see below), whose sum is σ = 243453072. Its totient is φ = 182589792.

The previous prime is 213021427. The next prime is 213021433. The reversal of 213021431 is 134120312.

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

It is not a de Polignac number, because 213021431 - 2² = 213021427 is a prime.

It is a super-2 number, since 2×213021431² = 90756260130575522, 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 (213021433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15215810 + ... + 15215823.

It is an arithmetic number, because the mean of its divisors is an integer number (60863268).

Almost surely, 2^213021431 is an apocalyptic number.

213021431 is a deficient number, since it is larger than the sum of its proper divisors (30431641).

213021431 is an equidigital number, since it uses as much as digits as its factorization.

213021431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30431640.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 213021431 is about 14595.2537148211. The cubic root of 213021431 is about 597.2292907189.

Adding to 213021431 its reverse (134120312), we get a palindrome (347141743).

The spelling of 213021431 in words is "two hundred thirteen million, twenty-one thousand, four hundred thirty-one".