221666629 has 2 divisors, whose sum is σ = 221666630. Its totient is φ = 221666628.

The previous prime is 221666579. The next prime is 221666659. The reversal of 221666629 is 926666122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 149450625 + 72216004 = 12225^2 + 8498^2 .

It is a cyclic number.

It is not a de Polignac number, because 221666629 - 2⁹ = 221666117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221666591 and 221666600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221666659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110833314 + 110833315.

It is an arithmetic number, because the mean of its divisors is an integer number (110833315).

Almost surely, 2^221666629 is an apocalyptic number.

It is an amenable number.

221666629 is a deficient number, since it is larger than the sum of its proper divisors (1).

221666629 is an equidigital number, since it uses as much as digits as its factorization.

221666629 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 93312, while the sum is 40.

The square root of 221666629 is about 14888.4730244575. The cubic root of 221666629 is about 605.2016530626.

The spelling of 221666629 in words is "two hundred twenty-one million, six hundred sixty-six thousand, six hundred twenty-nine".