221918985 has 24 divisors (see below), whose sum is σ = 385008000. Its totient is φ = 118249632.

The previous prime is 221918981. The next prime is 221918999. The reversal of 221918985 is 589819122.

221918985 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 221918985 - 2² = 221918981 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 221918985.

It is not an unprimeable number, because it can be changed into a prime (221918981) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 88722 + ... + 91188.

It is an arithmetic number, because the mean of its divisors is an integer number (16042000).

Almost surely, 2^221918985 is an apocalyptic number.

It is an amenable number.

221918985 is a deficient number, since it is larger than the sum of its proper divisors (163089015).

221918985 is a wasteful number, since it uses less digits than its factorization.

221918985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4477 (or 4474 counting only the distinct ones).

The product of its digits is 103680, while the sum is 45.

The square root of 221918985 is about 14896.9454922813. The cubic root of 221918985 is about 605.4312295648.

The spelling of 221918985 in words is "two hundred twenty-one million, nine hundred eighteen thousand, nine hundred eighty-five".