81440351 has 2 divisors, whose sum is σ = 81440352. Its totient is φ = 81440350.

The previous prime is 81440341. The next prime is 81440371. The reversal of 81440351 is 15304418.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81440351 - 2⁶ = 81440287 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a plaindrome in base 12.

It is a self number, because there is not a number n which added to its sum of digits gives 81440351.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81440321) 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, 40720175 + 40720176.

It is an arithmetic number, because the mean of its divisors is an integer number (40720176).

Almost surely, 2^81440351 is an apocalyptic number.

81440351 is a deficient number, since it is larger than the sum of its proper divisors (1).

81440351 is an equidigital number, since it uses as much as digits as its factorization.

81440351 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 81440351 is about 9024.4307853737. The cubic root of 81440351 is about 433.4575237076.

Adding to 81440351 its reverse (15304418), we get a palindrome (96744769).

The spelling of 81440351 in words is "eighty-one million, four hundred forty thousand, three hundred fifty-one".