221128907 has 2 divisors, whose sum is σ = 221128908. Its totient is φ = 221128906.

The previous prime is 221128891. The next prime is 221128927. The reversal of 221128907 is 709821122.

It is a happy number.

221128907 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 221128907 - 2⁴ = 221128891 is a prime.

It is a super-2 number, since 2×221128907² = 97795987022029298, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (221128927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110564453 + 110564454.

It is an arithmetic number, because the mean of its divisors is an integer number (110564454).

Almost surely, 2^221128907 is an apocalyptic number.

221128907 is a deficient number, since it is larger than the sum of its proper divisors (1).

221128907 is an equidigital number, since it uses as much as digits as its factorization.

221128907 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 221128907 is about 14870.4037268663. The cubic root of 221128907 is about 604.7118879525.

The spelling of 221128907 in words is "two hundred twenty-one million, one hundred twenty-eight thousand, nine hundred seven".