221221431 has 12 divisors (see below), whose sum is σ = 319671352. Its totient is φ = 147421296.

The previous prime is 221221423. The next prime is 221221447. The reversal of 221221431 is 134122122.

It is a happy number.

221221431 is a `hidden beast` number, since 2 + 212 + 21 + 431 = 666.

It is not a de Polignac number, because 221221431 - 2³ = 221221423 is a prime.

It is a super-2 number, since 2×221221431² = 97877843067375522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221221421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38700 + ... + 44046.

Almost surely, 2^221221431 is an apocalyptic number.

221221431 is a deficient number, since it is larger than the sum of its proper divisors (98449921).

221221431 is a wasteful number, since it uses less digits than its factorization.

221221431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9950 (or 9947 counting only the distinct ones).

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

The square root of 221221431 is about 14873.5144132112. The cubic root of 221221431 is about 604.7962166845.

Adding to 221221431 its reverse (134122122), we get a palindrome (355343553).

The spelling of 221221431 in words is "two hundred twenty-one million, two hundred twenty-one thousand, four hundred thirty-one".