221690087 has 2 divisors, whose sum is σ = 221690088. Its totient is φ = 221690086.

The previous prime is 221690041. The next prime is 221690089. The reversal of 221690087 is 780096122.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221690087 - 2¹⁶ = 221624551 is a prime.

Together with 221690089, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221690089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110845043 + 110845044.

It is an arithmetic number, because the mean of its divisors is an integer number (110845044).

Almost surely, 2^221690087 is an apocalyptic number.

221690087 is a deficient number, since it is larger than the sum of its proper divisors (1).

221690087 is an equidigital number, since it uses as much as digits as its factorization.

221690087 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 221690087 is about 14889.2607942772. The cubic root of 221690087 is about 605.2230009153.

The spelling of 221690087 in words is "two hundred twenty-one million, six hundred ninety thousand, eighty-seven".