20898791 has 4 divisors (see below), whose sum is σ = 20908800. Its totient is φ = 20888784.

The previous prime is 20898767. The next prime is 20898793. The reversal of 20898791 is 19789802.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20898791 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20898793) 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 3 ways as a sum of consecutive naturals, for example, 551 + ... + 6488.

It is an arithmetic number, because the mean of its divisors is an integer number (5227200).

Almost surely, 2^20898791 is an apocalyptic number.

20898791 is a deficient number, since it is larger than the sum of its proper divisors (10009).

20898791 is an equidigital number, since it uses as much as digits as its factorization.

20898791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10008.

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 20898791 is about 4571.5195504340. The cubic root of 20898791 is about 275.4484847184.

The spelling of 20898791 in words is "twenty million, eight hundred ninety-eight thousand, seven hundred ninety-one".