221918797 has 2 divisors, whose sum is σ = 221918798. Its totient is φ = 221918796.

The previous prime is 221918771. The next prime is 221918857. The reversal of 221918797 is 797819122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144144036 + 77774761 = 12006^2 + 8819^2 .

It is a cyclic number.

It is not a de Polignac number, because 221918797 - 2¹⁵ = 221886029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221918717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110959398 + 110959399.

It is an arithmetic number, because the mean of its divisors is an integer number (110959399).

Almost surely, 2^221918797 is an apocalyptic number.

It is an amenable number.

221918797 is a deficient number, since it is larger than the sum of its proper divisors (1).

221918797 is an equidigital number, since it uses as much as digits as its factorization.

221918797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 127008, while the sum is 46.

The square root of 221918797 is about 14896.9391822616. The cubic root of 221918797 is about 605.4310585998.

The spelling of 221918797 in words is "two hundred twenty-one million, nine hundred eighteen thousand, seven hundred ninety-seven".