221012644 has 12 divisors (see below), whose sum is σ = 390602268. Its totient is φ = 109412000.

The previous prime is 221012633. The next prime is 221012663. The reversal of 221012644 is 446210122.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 206267044 + 14745600 = 14362^2 + 3840^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 273127 + ... + 273934.

It is an arithmetic number, because the mean of its divisors is an integer number (32550189).

Almost surely, 2^221012644 is an apocalyptic number.

It is an amenable number.

221012644 is a deficient number, since it is larger than the sum of its proper divisors (169589624).

221012644 is a wasteful number, since it uses less digits than its factorization.

221012644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 547166 (or 547164 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 221012644 is about 14866.4940049764. The cubic root of 221012644 is about 604.6058895338.

Adding to 221012644 its reverse (446210122), we get a palindrome (667222766).

The spelling of 221012644 in words is "two hundred twenty-one million, twelve thousand, six hundred forty-four".