221681012 has 12 divisors (see below), whose sum is σ = 443362080. Its totient is φ = 95006136.

The previous prime is 221681011. The next prime is 221681021. The reversal of 221681012 is 210186122.

221681012 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221681011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3958562 + ... + 3958617.

It is an arithmetic number, because the mean of its divisors is an integer number (36946840).

Almost surely, 2^221681012 is an apocalyptic number.

It is an amenable number.

221681012 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221681012 is a wasteful number, since it uses less digits than its factorization.

221681012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7917190 (or 7917188 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 221681012 is about 14888.9560413079. The cubic root of 221681012 is about 605.2147424289.

The spelling of 221681012 in words is "two hundred twenty-one million, six hundred eighty-one thousand, twelve".