128333021 has 2 divisors, whose sum is σ = 128333022. Its totient is φ = 128333020.

The previous prime is 128332991. The next prime is 128333053. The reversal of 128333021 is 120333821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 111408025 + 16924996 = 10555^2 + 4114^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128333021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128333921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64166510 + 64166511.

It is an arithmetic number, because the mean of its divisors is an integer number (64166511).

Almost surely, 2^128333021 is an apocalyptic number.

It is an amenable number.

128333021 is a deficient number, since it is larger than the sum of its proper divisors (1).

128333021 is an equidigital number, since it uses as much as digits as its factorization.

128333021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 128333021 is about 11328.4165265936. The cubic root of 128333021 is about 504.4051041406.

Adding to 128333021 its reverse (120333821), we get a palindrome (248666842).

The spelling of 128333021 in words is "one hundred twenty-eight million, three hundred thirty-three thousand, twenty-one".