128821711 has 2 divisors, whose sum is σ = 128821712. Its totient is φ = 128821710.

The previous prime is 128821703. The next prime is 128821757. The reversal of 128821711 is 117128821.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 128821711 - 2³ = 128821703 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128821211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64410855 + 64410856.

It is an arithmetic number, because the mean of its divisors is an integer number (64410856).

Almost surely, 2^128821711 is an apocalyptic number.

128821711 is a deficient number, since it is larger than the sum of its proper divisors (1).

128821711 is an equidigital number, since it uses as much as digits as its factorization.

128821711 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1792, while the sum is 31.

The square root of 128821711 is about 11349.9652422375. The cubic root of 128821711 is about 505.0445485649.

The spelling of 128821711 in words is "one hundred twenty-eight million, eight hundred twenty-one thousand, seven hundred eleven".