20001121020 has 384 divisors, whose sum is σ = 68042419200. Its totient is φ = 4921274880.

The previous prime is 20001120977. The next prime is 20001121031. The reversal of 20001121020 is 2012110002.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 20001120993 and 20001121011.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 34073167 + ... + 34073753.

It is an arithmetic number, because the mean of its divisors is an integer number (177193800).

Almost surely, 2^20001121020 is an apocalyptic number.

20001121020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20001121020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34021209600).

20001121020 is an abundant number, since it is smaller than the sum of its proper divisors (48041298180).

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

20001121020 is a wasteful number, since it uses less digits than its factorization.

20001121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 677 (or 657 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 20001121020 its reverse (2012110002), we get a palindrome (22013231022).

The spelling of 20001121020 in words is "twenty billion, one million, one hundred twenty-one thousand, twenty".