20028581 has 8 divisors (see below), whose sum is σ = 20766240. Its totient is φ = 19301328.

The previous prime is 20028563. The next prime is 20028587. The reversal of 20028581 is 18582002.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20028581 - 2⁶ = 20028517 is a prime.

It is a super-2 number, since 2×20028581² = 802288113747122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20028581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20028587) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1430 + ... + 6488.

It is an arithmetic number, because the mean of its divisors is an integer number (2595780).

Almost surely, 2^20028581 is an apocalyptic number.

It is an amenable number.

20028581 is a deficient number, since it is larger than the sum of its proper divisors (737659).

20028581 is a wasteful number, since it uses less digits than its factorization.

20028581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5203.

The product of its (nonzero) digits is 1280, while the sum is 26.

The square root of 20028581 is about 4475.3302671423. The cubic root of 20028581 is about 271.5710013988.

The spelling of 20028581 in words is "twenty million, twenty-eight thousand, five hundred eighty-one".