128350721 has 2 divisors, whose sum is σ = 128350722. Its totient is φ = 128350720.

The previous prime is 128350693. The next prime is 128350751. The reversal of 128350721 is 127053821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 104448400 + 23902321 = 10220^2 + 4889^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128350721 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (128350751) by changing a digit.

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 as a sum of consecutive naturals, namely, 64175360 + 64175361.

It is an arithmetic number, because the mean of its divisors is an integer number (64175361).

Almost surely, 2^128350721 is an apocalyptic number.

It is an amenable number.

128350721 is a deficient number, since it is larger than the sum of its proper divisors (1).

128350721 is an equidigital number, since it uses as much as digits as its factorization.

128350721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 128350721 is about 11329.1977209333. The cubic root of 128350721 is about 504.4282926644.

The spelling of 128350721 in words is "one hundred twenty-eight million, three hundred fifty thousand, seven hundred twenty-one".