20011001820 has 24 divisors (see below), whose sum is σ = 56030805264. Its totient is φ = 5336267136.

The previous prime is 20011001753. The next prime is 20011001827. The reversal of 20011001820 is 2810011002.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 20011001820.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20011001827) 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, 166758289 + ... + 166758408.

It is an arithmetic number, because the mean of its divisors is an integer number (2334616886).

Almost surely, 2^20011001820 is an apocalyptic number.

20011001820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20011001820 is an abundant number, since it is smaller than the sum of its proper divisors (36019803444).

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

20011001820 is a wasteful number, since it uses less digits than its factorization.

20011001820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333516709 (or 333516707 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 20011001820 its reverse (2810011002), we get a palindrome (22821012822).

The spelling of 20011001820 in words is "twenty billion, eleven million, one thousand, eight hundred twenty".