100905128 has 16 divisors (see below), whose sum is σ = 189904500. Its totient is φ = 50263936.

The previous prime is 100905127. The next prime is 100905151. The reversal of 100905128 is 821509001.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 94051204 + 6853924 = 9698^2 + 2618^2 .

It is a junction number, because it is equal to n+sod(n) for n = 100905097 and 100905106.

It is not an unprimeable number, because it can be changed into a prime (100905127) 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, 21293 + ... + 25596.

Almost surely, 2^100905128 is an apocalyptic number.

It is an amenable number.

100905128 is a deficient number, since it is larger than the sum of its proper divisors (88999372).

100905128 is a wasteful number, since it uses less digits than its factorization.

100905128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47164 (or 47160 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 100905128 is about 10045.1544537653. The cubic root of 100905128 is about 465.5550899830. Note that the first 3 decimals are identical.

The spelling of 100905128 in words is "one hundred million, nine hundred five thousand, one hundred twenty-eight".