221790901 has 2 divisors, whose sum is σ = 221790902. Its totient is φ = 221790900.

The previous prime is 221790893. The next prime is 221790923. The reversal of 221790901 is 109097122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 221235876 + 555025 = 14874^2 + 745^2 .

It is a cyclic number.

It is not a de Polignac number, because 221790901 - 2³ = 221790893 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221790931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110895450 + 110895451.

It is an arithmetic number, because the mean of its divisors is an integer number (110895451).

Almost surely, 2^221790901 is an apocalyptic number.

It is an amenable number.

221790901 is a deficient number, since it is larger than the sum of its proper divisors (1).

221790901 is an equidigital number, since it uses as much as digits as its factorization.

221790901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2268, while the sum is 31.

The square root of 221790901 is about 14892.6458696902. The cubic root of 221790901 is about 605.3147291260.

The spelling of 221790901 in words is "two hundred twenty-one million, seven hundred ninety thousand, nine hundred one".