21235431181 has 2 divisors, whose sum is σ = 21235431182. Its totient is φ = 21235431180.

The previous prime is 21235431169. The next prime is 21235431193. The reversal of 21235431181 is 18113453212.

It is a balanced prime because it is at equal distance from previous prime (21235431169) and next prime (21235431193).

It can be written as a sum of positive squares in only one way, i.e., 20810659081 + 424772100 = 144259^2 + 20610^2 .

It is a cyclic number.

It is not a de Polignac number, because 21235431181 - 2²⁵ = 21201876749 is a prime.

It is a super-2 number, since 2×21235431181² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21235431131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617715590 + 10617715591.

It is an arithmetic number, because the mean of its divisors is an integer number (10617715591).

Almost surely, 2^21235431181 is an apocalyptic number.

It is an amenable number.

21235431181 is a deficient number, since it is larger than the sum of its proper divisors (1).

21235431181 is an equidigital number, since it uses as much as digits as its factorization.

21235431181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5760, while the sum is 31.

Adding to 21235431181 its reverse (18113453212), we get a palindrome (39348884393).

The spelling of 21235431181 in words is "twenty-one billion, two hundred thirty-five million, four hundred thirty-one thousand, one hundred eighty-one".