20810720871 has 12 divisors (see below), whose sum is σ = 30061220280. Its totient is φ = 13873218480.

The previous prime is 20810720857. The next prime is 20810720893. The reversal of 20810720871 is 17802701802.

It is a happy number.

It is not a de Polignac number, because 20810720871 - 2⁵ = 20810720839 is a prime.

It is a super-2 number, since 2×20810720871² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20810720831) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 305481 + ... + 367341.

It is an arithmetic number, because the mean of its divisors is an integer number (2505101690).

Almost surely, 2^20810720871 is an apocalyptic number.

20810720871 is a deficient number, since it is larger than the sum of its proper divisors (9250499409).

20810720871 is a wasteful number, since it uses less digits than its factorization.

20810720871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99246 (or 99243 counting only the distinct ones).

The product of its (nonzero) digits is 12544, while the sum is 36.

The spelling of 20810720871 in words is "twenty billion, eight hundred ten million, seven hundred twenty thousand, eight hundred seventy-one".