221279812 has 18 divisors (see below), whose sum is σ = 419319978. Its totient is φ = 102128832.

The previous prime is 221279809. The next prime is 221279813. The reversal of 221279812 is 218972122.

It can be written as a sum of positive squares in 3 ways, for example, as 23483716 + 197796096 = 4846^2 + 14064^2 .

It is not an unprimeable number, because it can be changed into a prime (221279813) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 162993 + ... + 164344.

Almost surely, 2^221279812 is an apocalyptic number.

It is an amenable number.

221279812 is a deficient number, since it is larger than the sum of its proper divisors (198040166).

221279812 is a wasteful number, since it uses less digits than its factorization.

221279812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327367 (or 327352 counting only the distinct ones).

The product of its digits is 8064, while the sum is 34.

The square root of 221279812 is about 14875.4768663058. The cubic root of 221279812 is about 604.8494145177.

The spelling of 221279812 in words is "two hundred twenty-one million, two hundred seventy-nine thousand, eight hundred twelve".