128625643 has 4 divisors (see below), whose sum is σ = 133061040. Its totient is φ = 124190248.

The previous prime is 128625631. The next prime is 128625661. The reversal of 128625643 is 346526821.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128625643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128625143) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2217655 + ... + 2217712.

It is an arithmetic number, because the mean of its divisors is an integer number (33265260).

Almost surely, 2^128625643 is an apocalyptic number.

128625643 is a deficient number, since it is larger than the sum of its proper divisors (4435397).

128625643 is an equidigital number, since it uses as much as digits as its factorization.

128625643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4435396.

The product of its digits is 69120, while the sum is 37.

The square root of 128625643 is about 11341.3245699080. The cubic root of 128625643 is about 504.7881907549.

The spelling of 128625643 in words is "one hundred twenty-eight million, six hundred twenty-five thousand, six hundred forty-three".