221311693 has 2 divisors, whose sum is σ = 221311694. Its totient is φ = 221311692.

The previous prime is 221311687. The next prime is 221311709. The reversal of 221311693 is 396113122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 212051844 + 9259849 = 14562^2 + 3043^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221311693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221311603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110655846 + 110655847.

It is an arithmetic number, because the mean of its divisors is an integer number (110655847).

Almost surely, 2^221311693 is an apocalyptic number.

It is an amenable number.

221311693 is a deficient number, since it is larger than the sum of its proper divisors (1).

221311693 is an equidigital number, since it uses as much as digits as its factorization.

221311693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 28.

The square root of 221311693 is about 14876.5484236096. The cubic root of 221311693 is about 604.8784611171.

The spelling of 221311693 in words is "two hundred twenty-one million, three hundred eleven thousand, six hundred ninety-three".