20811817000 has 64 divisors (see below), whose sum is σ = 52445811600. Its totient is φ = 7684358400.

The previous prime is 20811816997. The next prime is 20811817003. The reversal of 20811817000 is 71811802.

It is an interprime number because it is at equal distance from previous prime (20811816997) and next prime (20811817003).

It can be written as a sum of positive squares in 8 ways, for example, as 46430596 + 20765386404 = 6814^2 + 144102^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20811817000.

It is not an unprimeable number, because it can be changed into a prime (20811817003) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 787455 + ... + 813454.

Almost surely, 2^20811817000 is an apocalyptic number.

20811817000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20811817000 is an abundant number, since it is smaller than the sum of its proper divisors (31633994600).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20811817000 is a wasteful number, since it uses less digits than its factorization.

20811817000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1600943 (or 1600929 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 28.

The spelling of 20811817000 in words is "twenty billion, eight hundred eleven million, eight hundred seventeen thousand".