128264921 has 2 divisors, whose sum is σ = 128264922. Its totient is φ = 128264920.

The previous prime is 128264911. The next prime is 128264923. The reversal of 128264921 is 129462821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71639296 + 56625625 = 8464^2 + 7525^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128264921 is a prime.

Together with 128264923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (128264923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64132460 + 64132461.

It is an arithmetic number, because the mean of its divisors is an integer number (64132461).

Almost surely, 2^128264921 is an apocalyptic number.

It is an amenable number.

128264921 is a deficient number, since it is larger than the sum of its proper divisors (1).

128264921 is an equidigital number, since it uses as much as digits as its factorization.

128264921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 35.

The square root of 128264921 is about 11325.4104119895. The cubic root of 128264921 is about 504.3158673901.

The spelling of 128264921 in words is "one hundred twenty-eight million, two hundred sixty-four thousand, nine hundred twenty-one".