221731423 has 2 divisors, whose sum is σ = 221731424. Its totient is φ = 221731422.

The previous prime is 221731337. The next prime is 221731439. The reversal of 221731423 is 324137122.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221731423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221731483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110865711 + 110865712.

It is an arithmetic number, because the mean of its divisors is an integer number (110865712).

Almost surely, 2^221731423 is an apocalyptic number.

221731423 is a deficient number, since it is larger than the sum of its proper divisors (1).

221731423 is an equidigital number, since it uses as much as digits as its factorization.

221731423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2016, while the sum is 25.

The square root of 221731423 is about 14890.6488441572. The cubic root of 221731423 is about 605.2606149009.

Adding to 221731423 its reverse (324137122), we get a palindrome (545868545).

The spelling of 221731423 in words is "two hundred twenty-one million, seven hundred thirty-one thousand, four hundred twenty-three".