2128581 has 48 divisors (see below), whose sum is σ = 3983616. Its totient is φ = 1064448.

The previous prime is 2128561. The next prime is 2128591. The reversal of 2128581 is 1858212.

It is not a de Polignac number, because 2128581 - 2⁵ = 2128549 is a prime.

It is a super-2 number, since 2×2128581² = 9061714147122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2128501) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 18781 + ... + 18893.

It is an arithmetic number, because the mean of its divisors is an integer number (82992).

2^2128581 is an apocalyptic number.

2128581 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2128581 is a deficient number, since it is larger than the sum of its proper divisors (1855035).

2128581 is a wasteful number, since it uses less digits than its factorization.

2128581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 159 counting only the distinct ones).

The product of its digits is 1280, while the sum is 27.

The square root of 2128581 is about 1458.9657295495. The cubic root of 2128581 is about 128.6362567249.

The spelling of 2128581 in words is "two million, one hundred twenty-eight thousand, five hundred eighty-one".