128747821 has 2 divisors, whose sum is σ = 128747822. Its totient is φ = 128747820.

The previous prime is 128747789. The next prime is 128747833.

128747821 is nontrivially palindromic in base 10.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70056900 + 58690921 = 8370^2 + 7661^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 128747821 - 2⁵ = 128747789 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128747321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64373910 + 64373911.

It is an arithmetic number, because the mean of its divisors is an integer number (64373911).

Almost surely, 2^128747821 is an apocalyptic number.

It is an amenable number.

128747821 is a deficient number, since it is larger than the sum of its proper divisors (1).

128747821 is an equidigital number, since it uses as much as digits as its factorization.

128747821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 50176, while the sum is 40.

The square root of 128747821 is about 11346.7096992917. The cubic root of 128747821 is about 504.9479683673.

The spelling of 128747821 in words is "one hundred twenty-eight million, seven hundred forty-seven thousand, eight hundred twenty-one".