20121001984 has 56 divisors (see below), whose sum is σ = 42606874908. Its totient is φ = 9468641280.

The previous prime is 20121001973. The next prime is 20121001987. The reversal of 20121001984 is 48910012102.

It can be written as a sum of positive squares in 2 ways, for example, as 15209795584 + 4911206400 = 123328^2 + 70080^2 .

It is not an unprimeable number, because it can be changed into a prime (20121001987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67024 + ... + 211504.

Almost surely, 2^20121001984 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20121001984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21303437454).

20121001984 is an abundant number, since it is smaller than the sum of its proper divisors (22485872924).

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

20121001984 is an equidigital number, since it uses as much as digits as its factorization.

20121001984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144524 (or 144500 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 28.

The spelling of 20121001984 in words is "twenty billion, one hundred twenty-one million, one thousand, nine hundred eighty-four".