21001324133 has 6 divisors (see below), whose sum is σ = 21319459686. Its totient is φ = 20687867112.

The previous prime is 21001324129. The next prime is 21001324163. The reversal of 21001324133 is 33142310012.

It can be written as a sum of positive squares in only one way, i.e., 19815348289 + 1185975844 = 140767^2 + 34438^2 .

It is not a de Polignac number, because 21001324133 - 2² = 21001324129 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001324103) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2334710 + ... + 2343687.

It is an arithmetic number, because the mean of its divisors is an integer number (3553243281).

Almost surely, 2^21001324133 is an apocalyptic number.

It is an amenable number.

21001324133 is a deficient number, since it is larger than the sum of its proper divisors (318135553).

21001324133 is an frugal number, since it uses more digits than its factorization.

21001324133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4678531 (or 4678464 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21001324133 its reverse (33142310012), we get a palindrome (54143634145).

The spelling of 21001324133 in words is "twenty-one billion, one million, three hundred twenty-four thousand, one hundred thirty-three".