20100001820 has 12 divisors (see below), whose sum is σ = 42210003864. Its totient is φ = 8040000720.

The previous prime is 20100001793. The next prime is 20100001861. The reversal of 20100001820 is 2810000102.

It is a junction number, because it is equal to n+sod(n) for n = 20100001795 and 20100001804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 502500026 + ... + 502500065.

It is an arithmetic number, because the mean of its divisors is an integer number (3517500322).

Almost surely, 2^20100001820 is an apocalyptic number.

20100001820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20100001820 is an abundant number, since it is smaller than the sum of its proper divisors (22110002044).

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

20100001820 is a wasteful number, since it uses less digits than its factorization.

20100001820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1005000100 (or 1005000098 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 20100001820 its reverse (2810000102), we get a palindrome (22910001922).

The spelling of 20100001820 in words is "twenty billion, one hundred million, one thousand, eight hundred twenty".