21431331853 has 2 divisors, whose sum is σ = 21431331854. Its totient is φ = 21431331852.

The previous prime is 21431331841. The next prime is 21431331871. The reversal of 21431331853 is 35813313412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20592824004 + 838507849 = 143502^2 + 28957^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21431331853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21431331893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10715665926 + 10715665927.

It is an arithmetic number, because the mean of its divisors is an integer number (10715665927).

Almost surely, 2^21431331853 is an apocalyptic number.

It is an amenable number.

21431331853 is a deficient number, since it is larger than the sum of its proper divisors (1).

21431331853 is an equidigital number, since it uses as much as digits as its factorization.

21431331853 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25920, while the sum is 34.

The spelling of 21431331853 in words is "twenty-one billion, four hundred thirty-one million, three hundred thirty-one thousand, eight hundred fifty-three".