221921279 has 2 divisors, whose sum is σ = 221921280. Its totient is φ = 221921278.

The previous prime is 221921269. The next prime is 221921291. The reversal of 221921279 is 972129122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221921279 - 2¹⁶ = 221855743 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221921269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110960639 + 110960640.

It is an arithmetic number, because the mean of its divisors is an integer number (110960640).

Almost surely, 2^221921279 is an apocalyptic number.

221921279 is a deficient number, since it is larger than the sum of its proper divisors (1).

221921279 is an equidigital number, since it uses as much as digits as its factorization.

221921279 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 35.

The square root of 221921279 is about 14897.0224877322. The cubic root of 221921279 is about 605.4333156931.

The spelling of 221921279 in words is "two hundred twenty-one million, nine hundred twenty-one thousand, two hundred seventy-nine".