20865189 has 4 divisors (see below), whose sum is σ = 27820256. Its totient is φ = 13910124.

The previous prime is 20865179. The next prime is 20865193. The reversal of 20865189 is 98156802.

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 20865189 - 2⁹ = 20864677 is a prime.

It is a super-2 number, since 2×20865189² = 870712224011442, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20865109) 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, 3477529 + ... + 3477534.

It is an arithmetic number, because the mean of its divisors is an integer number (6955064).

Almost surely, 2^20865189 is an apocalyptic number.

It is an amenable number.

20865189 is a deficient number, since it is larger than the sum of its proper divisors (6955067).

20865189 is an equidigital number, since it uses as much as digits as its factorization.

20865189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6955066.

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

The square root of 20865189 is about 4567.8429263713. The cubic root of 20865189 is about 275.3007794445.

The spelling of 20865189 in words is "twenty million, eight hundred sixty-five thousand, one hundred eighty-nine".