221234442421 has 4 divisors (see below), whose sum is σ = 221512027212. Its totient is φ = 220956857632.

The previous prime is 221234442389. The next prime is 221234442449. The reversal of 221234442421 is 124244432122.

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 91180445521 + 130053996900 = 301961^2 + 360630^2 .

It is a cyclic number.

It is not a de Polignac number, because 221234442421 - 2⁵ = 221234442389 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 (221234442721) 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, 138791200 + ... + 138792793.

It is an arithmetic number, because the mean of its divisors is an integer number (55378006803).

Almost surely, 2^221234442421 is an apocalyptic number.

It is an amenable number.

221234442421 is a deficient number, since it is larger than the sum of its proper divisors (277584791).

221234442421 is an equidigital number, since it uses as much as digits as its factorization.

221234442421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277584790.

The product of its digits is 24576, while the sum is 31.

Adding to 221234442421 its reverse (124244432122), we get a palindrome (345478874543).

The spelling of 221234442421 in words is "two hundred twenty-one billion, two hundred thirty-four million, four hundred forty-two thousand, four hundred twenty-one".