128638356 has 96 divisors (see below), whose sum is σ = 390555648. Its totient is φ = 31954560.

The previous prime is 128638343. The next prime is 128638357. The reversal of 128638356 is 653836821.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128638357) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18226 + ... + 24278.

It is an arithmetic number, because the mean of its divisors is an integer number (4068288).

Almost surely, 2^128638356 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 128638356, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (195277824).

128638356 is an abundant number, since it is smaller than the sum of its proper divisors (261917292).

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

128638356 is a wasteful number, since it uses less digits than its factorization.

128638356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6101 (or 6099 counting only the distinct ones).

The product of its digits is 207360, while the sum is 42.

The square root of 128638356 is about 11341.8850285127. The cubic root of 128638356 is about 504.8048208263.

It can be divided in two parts, 12 and 8638356, that added together give a palindrome (8638368).

The spelling of 128638356 in words is "one hundred twenty-eight million, six hundred thirty-eight thousand, three hundred fifty-six".