128234640 has 40 divisors (see below), whose sum is σ = 397528128. Its totient is φ = 34195840.

The previous prime is 128234633. The next prime is 128234641. The reversal of 128234640 is 46432821.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 128234598 and 128234607.

It is not an unprimeable number, because it can be changed into a prime (128234641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 266916 + ... + 267395.

Almost surely, 2^128234640 is an apocalyptic number.

128234640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128234640 is an abundant number, since it is smaller than the sum of its proper divisors (269293488).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

128234640 is a wasteful number, since it uses less digits than its factorization.

128234640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534327 (or 534321 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 128234640 is about 11324.0734720329. The cubic root of 128234640 is about 504.2761776850.

The spelling of 128234640 in words is "one hundred twenty-eight million, two hundred thirty-four thousand, six hundred forty".