213042421 has 4 divisors (see below), whose sum is σ = 224255200. Its totient is φ = 201829644.

The previous prime is 213042413. The next prime is 213042433. The reversal of 213042421 is 124240312.

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 213042421 - 2³ = 213042413 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 11212759 = 213042421 / (2 + 1 + 3 + 0 + 4 + 2 + 4 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213042121) 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, 5606361 + ... + 5606398.

It is an arithmetic number, because the mean of its divisors is an integer number (56063800).

Almost surely, 2^213042421 is an apocalyptic number.

It is an amenable number.

213042421 is a deficient number, since it is larger than the sum of its proper divisors (11212779).

213042421 is a wasteful number, since it uses less digits than its factorization.

213042421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11212778.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 213042421 is about 14595.9727664860. The cubic root of 213042421 is about 597.2489060084.

Adding to 213042421 its reverse (124240312), we get a palindrome (337282733).

It can be divided in two parts, 2130 and 42421, that added together give a triangular number (44551 = T₂₉₈).

The spelling of 213042421 in words is "two hundred thirteen million, forty-two thousand, four hundred twenty-one".