221142431 has 2 divisors, whose sum is σ = 221142432. Its totient is φ = 221142430.

The previous prime is 221142413. The next prime is 221142491. The reversal of 221142431 is 134241122.

Together with previous prime (221142413) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221142431 - 2²⁶ = 154033567 is a prime.

It is a super-2 number, since 2×221142431² = 97807949577179522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221142491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110571215 + 110571216.

It is an arithmetic number, because the mean of its divisors is an integer number (110571216).

Almost surely, 2^221142431 is an apocalyptic number.

221142431 is a deficient number, since it is larger than the sum of its proper divisors (1).

221142431 is an equidigital number, since it uses as much as digits as its factorization.

221142431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 384, while the sum is 20.

The square root of 221142431 is about 14870.8584486572. The cubic root of 221142431 is about 604.7242155385.

Adding to 221142431 its reverse (134241122), we get a palindrome (355383553).

The spelling of 221142431 in words is "two hundred twenty-one million, one hundred forty-two thousand, four hundred thirty-one".