221291986 has 16 divisors (see below), whose sum is σ = 334053720. Its totient is φ = 109943680.

The previous prime is 221291929. The next prime is 221291989. The reversal of 221291986 is 689192122.

It can be written as a sum of positive squares in 4 ways, for example, as 78943225 + 142348761 = 8885^2 + 11931^2 .

It is not an unprimeable number, because it can be changed into a prime (221291989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 358350 + ... + 358966.

Almost surely, 2^221291986 is an apocalyptic number.

221291986 is a deficient number, since it is larger than the sum of its proper divisors (112761734).

221291986 is a wasteful number, since it uses less digits than its factorization.

221291986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1469.

The product of its digits is 31104, while the sum is 40.

The square root of 221291986 is about 14875.8860576438. The cubic root of 221291986 is about 604.8605065097.

The spelling of 221291986 in words is "two hundred twenty-one million, two hundred ninety-one thousand, nine hundred eighty-six".