221861797 has 2 divisors, whose sum is σ = 221861798. Its totient is φ = 221861796.

The previous prime is 221861791. The next prime is 221861807. The reversal of 221861797 is 797168122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 211964481 + 9897316 = 14559^2 + 3146^2 .

It is a cyclic number.

It is not a de Polignac number, because 221861797 - 2⁷ = 221861669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221861791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110930898 + 110930899.

It is an arithmetic number, because the mean of its divisors is an integer number (110930899).

Almost surely, 2^221861797 is an apocalyptic number.

It is an amenable number.

221861797 is a deficient number, since it is larger than the sum of its proper divisors (1).

221861797 is an equidigital number, since it uses as much as digits as its factorization.

221861797 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 43.

The square root of 221861797 is about 14895.0259147139. The cubic root of 221861797 is about 605.3792190293.

The spelling of 221861797 in words is "two hundred twenty-one million, eight hundred sixty-one thousand, seven hundred ninety-seven".