221890905 has 24 divisors (see below), whose sum is σ = 385414848. Its totient is φ = 118094496.

The previous prime is 221890897. The next prime is 221890957. The reversal of 221890905 is 509098122.

It is not a de Polignac number, because 221890905 - 2³ = 221890897 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 221890905.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17734 + ... + 27536.

It is an arithmetic number, because the mean of its divisors is an integer number (16058952).

Almost surely, 2^221890905 is an apocalyptic number.

It is an amenable number.

221890905 is a deficient number, since it is larger than the sum of its proper divisors (163523943).

221890905 is a wasteful number, since it uses less digits than its factorization.

221890905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10317 (or 10314 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 221890905 is about 14896.0029873789. The cubic root of 221890905 is about 605.4056928792.

The spelling of 221890905 in words is "two hundred twenty-one million, eight hundred ninety thousand, nine hundred five".