221231279 has 2 divisors, whose sum is σ = 221231280. Its totient is φ = 221231278.

The previous prime is 221231239. The next prime is 221231281. The reversal of 221231279 is 972132122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221231279 - 2¹² = 221227183 is a prime.

Together with 221231281, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221231239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110615639 + 110615640.

It is an arithmetic number, because the mean of its divisors is an integer number (110615640).

Almost surely, 2^221231279 is an apocalyptic number.

221231279 is a deficient number, since it is larger than the sum of its proper divisors (1).

221231279 is an equidigital number, since it uses as much as digits as its factorization.

221231279 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 29.

The square root of 221231279 is about 14873.8454678002. The cubic root of 221231279 is about 604.8051910181.

The spelling of 221231279 in words is "two hundred twenty-one million, two hundred thirty-one thousand, two hundred seventy-nine".