20905889 has 8 divisors (see below), whose sum is σ = 21205800. Its totient is φ = 20608000.

The previous prime is 20905877. The next prime is 20905901. The reversal of 20905889 is 98850902.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20905877) and next prime (20905901).

It can be written as a sum of positive squares in 4 ways, for example, as 7656289 + 13249600 = 2767^2 + 3640^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20905889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20901889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45119 + ... + 45579.

It is an arithmetic number, because the mean of its divisors is an integer number (2650725).

Almost surely, 2^20905889 is an apocalyptic number.

It is an amenable number.

20905889 is a deficient number, since it is larger than the sum of its proper divisors (299911).

20905889 is a wasteful number, since it uses less digits than its factorization.

20905889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1011.

The product of its (nonzero) digits is 51840, while the sum is 41.

The square root of 20905889 is about 4572.2958128275. The cubic root of 20905889 is about 275.4796653426.

The spelling of 20905889 in words is "twenty million, nine hundred five thousand, eight hundred eighty-nine".