20840381817 has 8 divisors (see below), whose sum is σ = 27788474880. Its totient is φ = 13892938320.

The previous prime is 20840381773. The next prime is 20840381843. The reversal of 20840381817 is 71818304802.

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

It is not a de Polignac number, because 20840381817 - 2¹⁶ = 20840316281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20840382817) 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, 81817 + ... + 219942.

It is an arithmetic number, because the mean of its divisors is an integer number (3473559360).

Almost surely, 2^20840381817 is an apocalyptic number.

It is an amenable number.

20840381817 is a deficient number, since it is larger than the sum of its proper divisors (6948093063).

20840381817 is a wasteful number, since it uses less digits than its factorization.

20840381817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324783.

The product of its (nonzero) digits is 86016, while the sum is 42.

The spelling of 20840381817 in words is "twenty billion, eight hundred forty million, three hundred eighty-one thousand, eight hundred seventeen".