21111331331 has 4 divisors (see below), whose sum is σ = 21272486664. Its totient is φ = 20950176000.

The previous prime is 21111331309. The next prime is 21111331349. The reversal of 21111331331 is 13313311112.

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

It is a cyclic number.

It is not a de Polignac number, because 21111331331 - 2¹⁴ = 21111314947 is a prime.

It is a super-2 number, since 2×21111331331² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21111331301) 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, 80577470 + ... + 80577731.

It is an arithmetic number, because the mean of its divisors is an integer number (5318121666).

Almost surely, 2^21111331331 is an apocalyptic number.

21111331331 is a deficient number, since it is larger than the sum of its proper divisors (161155333).

21111331331 is a wasteful number, since it uses less digits than its factorization.

21111331331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161155332.

The product of its digits is 162, while the sum is 20.

Adding to 21111331331 its reverse (13313311112), we get a palindrome (34424642443).

The spelling of 21111331331 in words is "twenty-one billion, one hundred eleven million, three hundred thirty-one thousand, three hundred thirty-one".