21121213133 has 4 divisors (see below), whose sum is σ = 21122520288. Its totient is φ = 21119905980.

The previous prime is 21121213121. The next prime is 21121213153. The reversal of 21121213133 is 33131212112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21121213133 - 2¹⁸ = 21120950989 is a prime.

It is a super-2 number, since 2×21121213133² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121213103) 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, 629033 + ... + 661758.

It is an arithmetic number, because the mean of its divisors is an integer number (5280630072).

Almost surely, 2^21121213133 is an apocalyptic number.

It is an amenable number.

21121213133 is a deficient number, since it is larger than the sum of its proper divisors (1307155).

21121213133 is a wasteful number, since it uses less digits than its factorization.

21121213133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1307154.

The product of its digits is 216, while the sum is 20.

Adding to 21121213133 its reverse (33131212112), we get a palindrome (54252425245).

The spelling of 21121213133 in words is "twenty-one billion, one hundred twenty-one million, two hundred thirteen thousand, one hundred thirty-three".