221128387 has 2 divisors, whose sum is σ = 221128388. Its totient is φ = 221128386.

The previous prime is 221128379. The next prime is 221128483. The reversal of 221128387 is 783821122.

221128387 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221128387 - 2³ = 221128379 is a prime.

It is not a weakly prime, because it can be changed into another prime (221122387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110564193 + 110564194.

It is an arithmetic number, because the mean of its divisors is an integer number (110564194).

Almost surely, 2^221128387 is an apocalyptic number.

221128387 is a deficient number, since it is larger than the sum of its proper divisors (1).

221128387 is an equidigital number, since it uses as much as digits as its factorization.

221128387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 34.

The square root of 221128387 is about 14870.3862424619. The cubic root of 221128387 is about 604.7114139447.

The spelling of 221128387 in words is "two hundred twenty-one million, one hundred twenty-eight thousand, three hundred eighty-seven".