209120878928 has 20 divisors (see below), whose sum is σ = 436338757428. Its totient is φ = 96517328640.

The previous prime is 209120878909. The next prime is 209120878951. The reversal of 209120878928 is 829878021902.

It can be written as a sum of positive squares in 2 ways, for example, as 137335465744 + 71785413184 = 370588^2 + 267928^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 502694213 + ... + 502694628.

Almost surely, 2^209120878928 is an apocalyptic number.

It is an amenable number.

209120878928 is an abundant number, since it is smaller than the sum of its proper divisors (227217878500).

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

209120878928 is a wasteful number, since it uses less digits than its factorization.

209120878928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1005388862 (or 1005388856 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 56.

The spelling of 209120878928 in words is "two hundred nine billion, one hundred twenty million, eight hundred seventy-eight thousand, nine hundred twenty-eight".