21031321133 has 4 divisors (see below), whose sum is σ = 21052848540. Its totient is φ = 21009793728.

The previous prime is 21031321127. The next prime is 21031321151. The reversal of 21031321133 is 33112313012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19483134724 + 1548186409 = 139582^2 + 39347^2 .

It is a cyclic number.

It is not a de Polignac number, because 21031321133 - 2²² = 21027126829 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 (21031321153) 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, 10762238 + ... + 10764191.

It is an arithmetic number, because the mean of its divisors is an integer number (5263212135).

Almost surely, 2^21031321133 is an apocalyptic number.

It is an amenable number.

21031321133 is a deficient number, since it is larger than the sum of its proper divisors (21527407).

21031321133 is an equidigital number, since it uses as much as digits as its factorization.

21031321133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21527406.

The product of its (nonzero) digits is 324, while the sum is 20.

Adding to 21031321133 its reverse (33112313012), we get a palindrome (54143634145).

The spelling of 21031321133 in words is "twenty-one billion, thirty-one million, three hundred twenty-one thousand, one hundred thirty-three".