221306693 has 2 divisors, whose sum is σ = 221306694. Its totient is φ = 221306692.

The previous prime is 221306689. The next prime is 221306749. The reversal of 221306693 is 396603122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 217798564 + 3508129 = 14758^2 + 1873^2 .

It is a cyclic number.

It is not a de Polignac number, because 221306693 - 2² = 221306689 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221306593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110653346 + 110653347.

It is an arithmetic number, because the mean of its divisors is an integer number (110653347).

Almost surely, 2^221306693 is an apocalyptic number.

It is an amenable number.

221306693 is a deficient number, since it is larger than the sum of its proper divisors (1).

221306693 is an equidigital number, since it uses as much as digits as its factorization.

221306693 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 32.

The square root of 221306693 is about 14876.3803729267. The cubic root of 221306693 is about 604.8739058297.

The spelling of 221306693 in words is "two hundred twenty-one million, three hundred six thousand, six hundred ninety-three".