221985787 has 2 divisors, whose sum is σ = 221985788. Its totient is φ = 221985786.

The previous prime is 221985733. The next prime is 221985793. The reversal of 221985787 is 787589122.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221985787 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221985787.

It is not a weakly prime, because it can be changed into another prime (221985287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110992893 + 110992894.

It is an arithmetic number, because the mean of its divisors is an integer number (110992894).

Almost surely, 2^221985787 is an apocalyptic number.

221985787 is a deficient number, since it is larger than the sum of its proper divisors (1).

221985787 is an equidigital number, since it uses as much as digits as its factorization.

221985787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 564480, while the sum is 49.

The square root of 221985787 is about 14899.1874610665. The cubic root of 221985787 is about 605.4919723917.

The spelling of 221985787 in words is "two hundred twenty-one million, nine hundred eighty-five thousand, seven hundred eighty-seven".