2128556840 has 32 divisors (see below), whose sum is σ = 4791928680. Its totient is φ = 850947072.

The previous prime is 2128556777. The next prime is 2128556851. The reversal of 2128556840 is 486558212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2023740196 + 104816644 = 44986^2 + 10238^2 .

It is a super-2 number, since 2×2128556840² = 9061508442221571200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62612 + ... + 90428.

Almost surely, 2^2128556840 is an apocalyptic number.

2128556840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2128556840 is an abundant number, since it is smaller than the sum of its proper divisors (2663371840).

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

2128556840 is a wasteful number, since it uses less digits than its factorization.

2128556840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29741 (or 29737 counting only the distinct ones).

The product of its (nonzero) digits is 153600, while the sum is 41.

The square root of 2128556840 is about 46136.2855028447. The cubic root of 2128556840 is about 1286.3577003703.

It can be divided in two parts, 21285 and 56840, that added together give a 7-th power (78125 = 5⁷).

The spelling of 2128556840 in words is "two billion, one hundred twenty-eight million, five hundred fifty-six thousand, eight hundred forty".