20856489 has 8 divisors (see below), whose sum is σ = 28144032. Its totient is φ = 13736640.

The previous prime is 20856461. The next prime is 20856491. The reversal of 20856489 is 98465802.

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

It is not a de Polignac number, because 20856489 - 2⁵ = 20856457 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20856489.

It is not an unprimeable number, because it can be changed into a prime (20856439) 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, 41632 + ... + 42129.

It is an arithmetic number, because the mean of its divisors is an integer number (3518004).

Almost surely, 2^20856489 is an apocalyptic number.

It is an amenable number.

20856489 is a deficient number, since it is larger than the sum of its proper divisors (7287543).

20856489 is an equidigital number, since it uses as much as digits as its factorization.

20856489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83847.

The product of its (nonzero) digits is 138240, while the sum is 42.

The square root of 20856489 is about 4566.8905176279. The cubic root of 20856489 is about 275.2625107640.

The spelling of 20856489 in words is "twenty million, eight hundred fifty-six thousand, four hundred eighty-nine".