20849620871 has 4 divisors (see below), whose sum is σ = 20854251432. Its totient is φ = 20844990312.

The previous prime is 20849620849. The next prime is 20849620889. The reversal of 20849620871 is 17802694802.

It is a happy number.

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 20849620871 - 2¹⁸ = 20849358727 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 (20849620271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2308520 + ... + 2317533.

It is an arithmetic number, because the mean of its divisors is an integer number (5213562858).

Almost surely, 2^20849620871 is an apocalyptic number.

20849620871 is a deficient number, since it is larger than the sum of its proper divisors (4630561).

20849620871 is an equidigital number, since it uses as much as digits as its factorization.

20849620871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4630560.

The product of its (nonzero) digits is 387072, while the sum is 47.

The spelling of 20849620871 in words is "twenty billion, eight hundred forty-nine million, six hundred twenty thousand, eight hundred seventy-one".