20581689 has 4 divisors (see below), whose sum is σ = 27442256. Its totient is φ = 13721124.

The previous prime is 20581681. The next prime is 20581703. The reversal of 20581689 is 98618502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20581689 - 2³ = 20581681 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20581681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3430279 + ... + 3430284.

It is an arithmetic number, because the mean of its divisors is an integer number (6860564).

Almost surely, 2^20581689 is an apocalyptic number.

It is an amenable number.

20581689 is a deficient number, since it is larger than the sum of its proper divisors (6860567).

20581689 is an equidigital number, since it uses as much as digits as its factorization.

20581689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6860566.

The product of its (nonzero) digits is 34560, while the sum is 39.

The square root of 20581689 is about 4536.7046410363. The cubic root of 20581689 is about 274.0482315151.

The spelling of 20581689 in words is "twenty million, five hundred eighty-one thousand, six hundred eighty-nine".