221210128 has 20 divisors (see below), whose sum is σ = 436682988. Its totient is φ = 108517760.

The previous prime is 221210111. The next prime is 221210131. The reversal of 221210128 is 821012122.

It can be written as a sum of positive squares in 2 ways, for example, as 71098624 + 150111504 = 8432^2 + 12252^2 .

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 129583 + ... + 131278.

Almost surely, 2^221210128 is an apocalyptic number.

It is an amenable number.

221210128 is a deficient number, since it is larger than the sum of its proper divisors (215472860).

221210128 is a wasteful number, since it uses less digits than its factorization.

221210128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260922 (or 260916 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 221210128 is about 14873.1344376362. The cubic root of 221210128 is about 604.7859161031.

The spelling of 221210128 in words is "two hundred twenty-one million, two hundred ten thousand, one hundred twenty-eight".