213123421 has 4 divisors (see below), whose sum is σ = 243569632. Its totient is φ = 182677212.

The previous prime is 213123401. The next prime is 213123439. The reversal of 213123421 is 124321312.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 213123421 - 2⁹ = 213122909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213123401) 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, 15223095 + ... + 15223108.

It is an arithmetic number, because the mean of its divisors is an integer number (60892408).

Almost surely, 2^213123421 is an apocalyptic number.

It is an amenable number.

213123421 is a deficient number, since it is larger than the sum of its proper divisors (30446211).

213123421 is an equidigital number, since it uses as much as digits as its factorization.

213123421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30446210.

The product of its digits is 288, while the sum is 19.

The square root of 213123421 is about 14598.7472407738. The cubic root of 213123421 is about 597.3245889504.

Adding to 213123421 its reverse (124321312), we get a palindrome (337444733).

It can be divided in two parts, 2131 and 23421, that added together give a palindrome (25552).

The spelling of 213123421 in words is "two hundred thirteen million, one hundred twenty-three thousand, four hundred twenty-one".