21008000831 has 2 divisors, whose sum is σ = 21008000832. Its totient is φ = 21008000830.

The previous prime is 21008000813. The next prime is 21008000851. The reversal of 21008000831 is 13800080012.

Together with previous prime (21008000813) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21008000831 is a prime.

It is a super-2 number, since 2×21008000831² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21008000797 and 21008000806.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21008000851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10504000415 + 10504000416.

It is an arithmetic number, because the mean of its divisors is an integer number (10504000416).

Almost surely, 2^21008000831 is an apocalyptic number.

21008000831 is a deficient number, since it is larger than the sum of its proper divisors (1).

21008000831 is an equidigital number, since it uses as much as digits as its factorization.

21008000831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 23.

Adding to 21008000831 its reverse (13800080012), we get a palindrome (34808080843).

The spelling of 21008000831 in words is "twenty-one billion, eight million, eight hundred thirty-one", and thus it is an aban number.