20121001000 has 64 divisors (see below), whose sum is σ = 47568764880. Its totient is φ = 7965388800.

The previous prime is 20121000989. The next prime is 20121001027. The reversal of 20121001000 is 10012102.

It can be written as a sum of positive squares in 8 ways, for example, as 250715556 + 19870285444 = 15834^2 + 140962^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6717 + ... + 200716.

Almost surely, 2^20121001000 is an apocalyptic number.

20121001000 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 20121001000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23784382440).

20121001000 is an abundant number, since it is smaller than the sum of its proper divisors (27447763880).

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

20121001000 is a wasteful number, since it uses less digits than its factorization.

20121001000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207551 (or 207537 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 7.

Adding to 20121001000 its reverse (10012102), we get a palindrome (20131013102).

The spelling of 20121001000 in words is "twenty billion, one hundred twenty-one million, one thousand".