128421057 has 24 divisors (see below), whose sum is σ = 183056160. Its totient is φ = 80081352.

The previous prime is 128421053. The next prime is 128421071. The reversal of 128421057 is 750124821.

It is not a de Polignac number, because 128421057 - 2² = 128421053 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128421053) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1625544 + ... + 1625622.

It is an arithmetic number, because the mean of its divisors is an integer number (7627340).

Almost surely, 2^128421057 is an apocalyptic number.

It is an amenable number.

128421057 is a deficient number, since it is larger than the sum of its proper divisors (54635103).

128421057 is an frugal number, since it uses more digits than its factorization.

128421057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 30.

The square root of 128421057 is about 11332.3014873414. The cubic root of 128421057 is about 504.5204178175.

Adding to 128421057 its reverse (750124821), we get a palindrome (878545878).

The spelling of 128421057 in words is "one hundred twenty-eight million, four hundred twenty-one thousand, fifty-seven".