81915011 has 2 divisors, whose sum is σ = 81915012. Its totient is φ = 81915010.

The previous prime is 81914999. The next prime is 81915013. The reversal of 81915011 is 11051918.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81915011 is a prime.

Together with 81915013, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81915013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40957505 + 40957506.

It is an arithmetic number, because the mean of its divisors is an integer number (40957506).

Almost surely, 2^81915011 is an apocalyptic number.

81915011 is a deficient number, since it is larger than the sum of its proper divisors (1).

81915011 is an equidigital number, since it uses as much as digits as its factorization.

81915011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 26.

The square root of 81915011 is about 9050.6911890750. The cubic root of 81915011 is about 434.2980019205.

Adding to 81915011 its reverse (11051918), we get a palindrome (92966929).

The spelling of 81915011 in words is "eighty-one million, nine hundred fifteen thousand, eleven".