2178991000 has 32 divisors (see below), whose sum is σ = 5098841280. Its totient is φ = 871596000.

The previous prime is 2178990991. The next prime is 2178991021. The reversal of 2178991000 is 1998712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1088496 + ... + 1090495.

It is an arithmetic number, because the mean of its divisors is an integer number (159338790).

Almost surely, 2^2178991000 is an apocalyptic number.

2178991000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2178991000 is an abundant number, since it is smaller than the sum of its proper divisors (2919850280).

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

2178991000 is a wasteful number, since it uses less digits than its factorization.

2178991000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2179012 (or 2178998 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 2178991000 is about 46679.6636663119. The cubic root of 2178991000 is about 1296.4381790077.

The spelling of 2178991000 in words is "two billion, one hundred seventy-eight million, nine hundred ninety-one thousand".