20668889 has 8 divisors (see below), whose sum is σ = 22021920. Its totient is φ = 19331136.

The previous prime is 20668873. The next prime is 20668891. The reversal of 20668889 is 98886602.

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

It is a cyclic number.

It is not a de Polignac number, because 20668889 - 2⁴ = 20668873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20668819) 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, 959 + ... + 6500.

It is an arithmetic number, because the mean of its divisors is an integer number (2752740).

Almost surely, 2^20668889 is an apocalyptic number.

It is an amenable number.

20668889 is a deficient number, since it is larger than the sum of its proper divisors (1353031).

20668889 is a wasteful number, since it uses less digits than its factorization.

20668889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7639.

The product of its (nonzero) digits is 331776, while the sum is 47.

The square root of 20668889 is about 4546.3049831704. The cubic root of 20668889 is about 274.4347131793.

The spelling of 20668889 in words is "twenty million, six hundred sixty-eight thousand, eight hundred eighty-nine".