21230020133 has 6 divisors (see below), whose sum is σ = 24696145926. Its totient is φ = 18197160072.

The previous prime is 21230020127. The next prime is 21230020153. The reversal of 21230020133 is 33102003212.

It can be written as a sum of positive squares in only one way, i.e., 18430234564 + 2799785569 = 135758^2 + 52913^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21230020133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230020153) 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, 216632810 + ... + 216632907.

It is an arithmetic number, because the mean of its divisors is an integer number (4116024321).

Almost surely, 2^21230020133 is an apocalyptic number.

It is an amenable number.

21230020133 is a deficient number, since it is larger than the sum of its proper divisors (3466125793).

21230020133 is an equidigital number, since it uses as much as digits as its factorization.

21230020133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433265731 (or 433265724 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 17.

Adding to 21230020133 its reverse (33102003212), we get a palindrome (54332023345).

The spelling of 21230020133 in words is "twenty-one billion, two hundred thirty million, twenty thousand, one hundred thirty-three".