21031112321 has 2 divisors, whose sum is σ = 21031112322. Its totient is φ = 21031112320.

The previous prime is 21031112303. The next prime is 21031112363. The reversal of 21031112321 is 12321113012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17646199921 + 3384912400 = 132839^2 + 58180^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21031112321 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21031112321.

It is not a weakly prime, because it can be changed into another prime (21031112381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515556160 + 10515556161.

It is an arithmetic number, because the mean of its divisors is an integer number (10515556161).

Almost surely, 2^21031112321 is an apocalyptic number.

It is an amenable number.

21031112321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21031112321 is an equidigital number, since it uses as much as digits as its factorization.

21031112321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21031112321 its reverse (12321113012), we get a palindrome (33352225333).

The spelling of 21031112321 in words is "twenty-one billion, thirty-one million, one hundred twelve thousand, three hundred twenty-one".