128890820 has 12 divisors (see below), whose sum is σ = 270670764. Its totient is φ = 51556320.

The previous prime is 128890807. The next prime is 128890829. The reversal of 128890820 is 28098821.

It can be written as a sum of positive squares in 2 ways, for example, as 22429696 + 106461124 = 4736^2 + 10318^2 .

It is a super-2 number, since 2×128890820² = 33225686960544800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (128890829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3222251 + ... + 3222290.

It is an arithmetic number, because the mean of its divisors is an integer number (22555897).

Almost surely, 2^128890820 is an apocalyptic number.

128890820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128890820 is an abundant number, since it is smaller than the sum of its proper divisors (141779944).

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

128890820 is a wasteful number, since it uses less digits than its factorization.

128890820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6444550 (or 6444548 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 38.

The square root of 128890820 is about 11353.0092926942. The cubic root of 128890820 is about 505.1348461910.

It can be divided in two parts, 1288 and 90820, that multiplied together give a triangular number (116976160 = T₁₅₂₉₅).

The spelling of 128890820 in words is "one hundred twenty-eight million, eight hundred ninety thousand, eight hundred twenty".