21001324001 has 12 divisors (see below), whose sum is σ = 24671999700. Its totient is φ = 17822901600.

The previous prime is 21001323997. The next prime is 21001324013. The reversal of 21001324001 is 10042310012.

It can be written as a sum of positive squares in 2 ways, for example, as 10885792225 + 10115531776 = 104335^2 + 100576^2 .

It is not a de Polignac number, because 21001324001 - 2² = 21001323997 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001324021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2116826 + ... + 2126723.

It is an arithmetic number, because the mean of its divisors is an integer number (2055999975).

Almost surely, 2^21001324001 is an apocalyptic number.

It is an amenable number.

21001324001 is a deficient number, since it is larger than the sum of its proper divisors (3670675699).

21001324001 is a wasteful number, since it uses less digits than its factorization.

21001324001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4243664 (or 4243657 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21001324001 its reverse (10042310012), we get a palindrome (31043634013).

The spelling of 21001324001 in words is "twenty-one billion, one million, three hundred twenty-four thousand, one".