221009764 has 6 divisors (see below), whose sum is σ = 386767094. Its totient is φ = 110504880.

The previous prime is 221009743. The next prime is 221009777. The reversal of 221009764 is 467900122.

221009764 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 129960000 + 91049764 = 11400^2 + 9542^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27626217 + ... + 27626224.

Almost surely, 2^221009764 is an apocalyptic number.

It is an amenable number.

221009764 is a deficient number, since it is larger than the sum of its proper divisors (165757330).

221009764 is a wasteful number, since it uses less digits than its factorization.

221009764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55252445 (or 55252443 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 221009764 is about 14866.3971425494. The cubic root of 221009764 is about 604.6032633303.

Adding to 221009764 its reverse (467900122), we get a palindrome (688909886).

The spelling of 221009764 in words is "two hundred twenty-one million, nine thousand, seven hundred sixty-four".