21531236133 has 8 divisors (see below), whose sum is σ = 31318161696. Its totient is φ = 13049234000.

The previous prime is 21531236131. The next prime is 21531236159. The reversal of 21531236133 is 33163213512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21531236133 - 2¹ = 21531236131 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21531236133.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21531236131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 326230818 + ... + 326230883.

It is an arithmetic number, because the mean of its divisors is an integer number (3914770212).

Almost surely, 2^21531236133 is an apocalyptic number.

It is an amenable number.

21531236133 is a deficient number, since it is larger than the sum of its proper divisors (9786925563).

21531236133 is a wasteful number, since it uses less digits than its factorization.

21531236133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 652461715.

The product of its digits is 9720, while the sum is 30.

Adding to 21531236133 its reverse (33163213512), we get a palindrome (54694449645).

The spelling of 21531236133 in words is "twenty-one billion, five hundred thirty-one million, two hundred thirty-six thousand, one hundred thirty-three".