20028861 has 6 divisors (see below), whose sum is σ = 28930590. Its totient is φ = 13352568.

The previous prime is 20028829. The next prime is 20028863. The reversal of 20028861 is 16882002.

It can be written as a sum of positive squares in only one way, i.e., 19980900 + 47961 = 4470^2 + 219^2 .

It is not a de Polignac number, because 20028861 - 2⁵ = 20028829 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20028863) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1112706 + ... + 1112723.

It is an arithmetic number, because the mean of its divisors is an integer number (4821765).

Almost surely, 2^20028861 is an apocalyptic number.

It is an amenable number.

20028861 is a deficient number, since it is larger than the sum of its proper divisors (8901729).

20028861 is a wasteful number, since it uses less digits than its factorization.

20028861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2225435 (or 2225432 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 20028861 is about 4475.3615496404. The cubic root of 20028861 is about 271.5722669158.

The spelling of 20028861 in words is "twenty million, twenty-eight thousand, eight hundred sixty-one".