213222421 has 4 divisors (see below), whose sum is σ = 215178700. Its totient is φ = 211266144.

The previous prime is 213222407. The next prime is 213222437. The reversal of 213222421 is 124222312.

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

It can be written as a sum of positive squares in 2 ways, for example, as 177688900 + 35533521 = 13330^2 + 5961^2 .

It is a cyclic number.

It is not a de Polignac number, because 213222421 - 2⁷ = 213222293 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 (213222461) 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, 977976 + ... + 978193.

It is an arithmetic number, because the mean of its divisors is an integer number (53794675).

Almost surely, 2^213222421 is an apocalyptic number.

It is an amenable number.

213222421 is a deficient number, since it is larger than the sum of its proper divisors (1956279).

213222421 is a wasteful number, since it uses less digits than its factorization.

213222421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1956278.

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

The square root of 213222421 is about 14602.1375490029. The cubic root of 213222421 is about 597.4170642868.

Adding to 213222421 its reverse (124222312), we get a palindrome (337444733).

The spelling of 213222421 in words is "two hundred thirteen million, two hundred twenty-two thousand, four hundred twenty-one".