20909859 has 8 divisors (see below), whose sum is σ = 28126992. Its totient is φ = 13816320.

The previous prime is 20909857. The next prime is 20909869. The reversal of 20909859 is 95890902.

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

It is not a de Polignac number, because 20909859 - 2¹ = 20909857 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20909859.

It is not an unprimeable number, because it can be changed into a prime (20909851) 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, 30502 + ... + 31179.

It is an arithmetic number, because the mean of its divisors is an integer number (3515874).

Almost surely, 2^20909859 is an apocalyptic number.

20909859 is a deficient number, since it is larger than the sum of its proper divisors (7217133).

20909859 is a wasteful number, since it uses less digits than its factorization.

20909859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61797.

The product of its (nonzero) digits is 58320, while the sum is 42.

The square root of 20909859 is about 4572.7299286094. The cubic root of 20909859 is about 275.4971019773.

The spelling of 20909859 in words is "twenty million, nine hundred nine thousand, eight hundred fifty-nine".