128828621 has 2 divisors, whose sum is σ = 128828622. Its totient is φ = 128828620.

The previous prime is 128828617. The next prime is 128828633. The reversal of 128828621 is 126828821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 122899396 + 5929225 = 11086^2 + 2435^2 .

It is a cyclic number.

It is not a de Polignac number, because 128828621 - 2² = 128828617 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128828611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64414310 + 64414311.

It is an arithmetic number, because the mean of its divisors is an integer number (64414311).

Almost surely, 2^128828621 is an apocalyptic number.

It is an amenable number.

128828621 is a deficient number, since it is larger than the sum of its proper divisors (1).

128828621 is an equidigital number, since it uses as much as digits as its factorization.

128828621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24576, while the sum is 38.

The square root of 128828621 is about 11350.2696443741. The cubic root of 128828621 is about 505.0535786044.

The spelling of 128828621 in words is "one hundred twenty-eight million, eight hundred twenty-eight thousand, six hundred twenty-one".