2128681 has 3 divisors (see below), whose sum is σ = 2130141. Its totient is φ = 2127222.

The previous prime is 2128669. The next prime is 2128697. The reversal of 2128681 is 1868212.

The square root of 2128681 is 1459.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 2128681 - 2⁵ = 2128649 is a prime.

It is a super-2 number, since 2×2128681² = 9062565599522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2128601) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 730 + ... + 2188.

It is an arithmetic number, because the mean of its divisors is an integer number (710047).

2^2128681 is an apocalyptic number.

2128681 is the 1459-th square number.

2128681 is the 730-th centered octagonal number.

It is an amenable number.

2128681 is a deficient number, since it is larger than the sum of its proper divisors (1460).

2128681 is an frugal number, since it uses more digits than its factorization.

2128681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2918 (or 1459 counting only the distinct ones).

The product of its digits is 1536, while the sum is 28.

The cubic root of 2128681 is about 128.6382711223.

It can be divided in two parts, 2128 and 681, that added together give a square (2809 = 53²).

The spelling of 2128681 in words is "two million, one hundred twenty-eight thousand, six hundred eighty-one".