28331813381 has 2 divisors, whose sum is σ = 28331813382. Its totient is φ = 28331813380.

The previous prime is 28331813327. The next prime is 28331813417. The reversal of 28331813381 is 18331813382.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26063196481 + 2268616900 = 161441^2 + 47630^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28331813381 is a prime.

It is a super-2 number, since 2×28331813381² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28331833381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14165906690 + 14165906691.

It is an arithmetic number, because the mean of its divisors is an integer number (14165906691).

Almost surely, 2^28331813381 is an apocalyptic number.

It is an amenable number.

28331813381 is a deficient number, since it is larger than the sum of its proper divisors (1).

28331813381 is an equidigital number, since it uses as much as digits as its factorization.

28331813381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82944, while the sum is 41.

Subtracting from 28331813381 its reverse (18331813382), we obtain a palindrome (9999999999).

The spelling of 28331813381 in words is "twenty-eight billion, three hundred thirty-one million, eight hundred thirteen thousand, three hundred eighty-one".