221231421 has 24 divisors (see below), whose sum is σ = 356166720. Its totient is φ = 131504256.

The previous prime is 221231393. The next prime is 221231429. The reversal of 221231421 is 124132122.

It is a happy number.

221231421 is a `hidden beast` number, since 2 + 212 + 31 + 421 = 666.

It is not a de Polignac number, because 221231421 - 2⁵ = 221231389 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 221231394 and 221231403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221231429) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35145 + ... + 40958.

It is an arithmetic number, because the mean of its divisors is an integer number (14840280).

Almost surely, 2^221231421 is an apocalyptic number.

It is an amenable number.

221231421 is a deficient number, since it is larger than the sum of its proper divisors (134935299).

221231421 is a wasteful number, since it uses less digits than its factorization.

221231421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76145 (or 76142 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 221231421 is about 14873.8502412792. The cubic root of 221231421 is about 604.8053204186.

Adding to 221231421 its reverse (124132122), we get a palindrome (345363543).

It can be divided in two parts, 2212 and 31421, that added together give a palindrome (33633).

The spelling of 221231421 in words is "two hundred twenty-one million, two hundred thirty-one thousand, four hundred twenty-one".