81315887011 has 2 divisors, whose sum is σ = 81315887012. Its totient is φ = 81315887010.

The previous prime is 81315886979. The next prime is 81315887057. The reversal of 81315887011 is 11078851318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81315887011 - 2⁵ = 81315886979 is a prime.

It is a super-2 number, since 2×81315887011² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81315887911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40657943505 + 40657943506.

It is an arithmetic number, because the mean of its divisors is an integer number (40657943506).

Almost surely, 2^81315887011 is an apocalyptic number.

81315887011 is a deficient number, since it is larger than the sum of its proper divisors (1).

81315887011 is an equidigital number, since it uses as much as digits as its factorization.

81315887011 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 53760, while the sum is 43.

The spelling of 81315887011 in words is "eighty-one billion, three hundred fifteen million, eight hundred eighty-seven thousand, eleven".