221719691 has 2 divisors, whose sum is σ = 221719692. Its totient is φ = 221719690.

The previous prime is 221719679. The next prime is 221719697. The reversal of 221719691 is 196917122.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221719691 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221719697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110859845 + 110859846.

It is an arithmetic number, because the mean of its divisors is an integer number (110859846).

Almost surely, 2^221719691 is an apocalyptic number.

221719691 is a deficient number, since it is larger than the sum of its proper divisors (1).

221719691 is an equidigital number, since it uses as much as digits as its factorization.

221719691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13608, while the sum is 38.

The square root of 221719691 is about 14890.2549004374. The cubic root of 221719691 is about 605.2499397596.

The spelling of 221719691 in words is "two hundred twenty-one million, seven hundred nineteen thousand, six hundred ninety-one".