20006891 has 8 divisors (see below), whose sum is σ = 20388480. Its totient is φ = 19628352.

The previous prime is 20006887. The next prime is 20006923. The reversal of 20006891 is 19860002.

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 20006891 - 2² = 20006887 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20006891.

It is not an unprimeable number, because it can be changed into a prime (20006801) 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, 15665 + ... + 16893.

It is an arithmetic number, because the mean of its divisors is an integer number (2548560).

Almost surely, 2^20006891 is an apocalyptic number.

20006891 is a deficient number, since it is larger than the sum of its proper divisors (381589).

20006891 is a wasteful number, since it uses less digits than its factorization.

20006891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1525.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 20006891 is about 4472.9063258691. The cubic root of 20006891 is about 271.4729331660.

Adding to 20006891 its reverse (19860002), we get a palindrome (39866893).

The spelling of 20006891 in words is "twenty million, six thousand, eight hundred ninety-one".