20889647 has 4 divisors (see below), whose sum is σ = 20904240. Its totient is φ = 20875056.

The previous prime is 20889643. The next prime is 20889679. The reversal of 20889647 is 74698802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20889647 - 2² = 20889643 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20889598 and 20889607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20889643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4883 + ... + 8100.

It is an arithmetic number, because the mean of its divisors is an integer number (5226060).

Almost surely, 2^20889647 is an apocalyptic number.

20889647 is a deficient number, since it is larger than the sum of its proper divisors (14593).

20889647 is a wasteful number, since it uses less digits than its factorization.

20889647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14592.

The product of its (nonzero) digits is 193536, while the sum is 44.

The square root of 20889647 is about 4570.5193359180. The cubic root of 20889647 is about 275.4083058651.

The spelling of 20889647 in words is "twenty million, eight hundred eighty-nine thousand, six hundred forty-seven".