128789820 has 36 divisors (see below), whose sum is σ = 390663000. Its totient is φ = 34343904.

The previous prime is 128789819. The next prime is 128789821. The reversal of 128789820 is 28987821.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (128789819) and next prime (128789821).

It is a tau number, because it is divible by the number of its divisors (36).

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128789821) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 357570 + ... + 357929.

It is an arithmetic number, because the mean of its divisors is an integer number (10851750).

Almost surely, 2^128789820 is an apocalyptic number.

128789820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128789820 is an abundant number, since it is smaller than the sum of its proper divisors (261873180).

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

128789820 is a wasteful number, since it uses less digits than its factorization.

128789820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 715514 (or 715509 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The square root of 128789820 is about 11348.5602611080. The cubic root of 128789820 is about 505.0028689835.

The spelling of 128789820 in words is "one hundred twenty-eight million, seven hundred eighty-nine thousand, eight hundred twenty".