81000797787 has 192 divisors, whose sum is σ = 158304916224. Its totient is φ = 38698352640.

The previous prime is 81000797783. The next prime is 81000797789. The reversal of 81000797787 is 78779700018.

It is not a de Polignac number, because 81000797787 - 2² = 81000797783 is a prime.

It is a super-2 number, since 2×81000797787² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81000797783) 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 in 191 ways as a sum of consecutive naturals, for example, 49968837 + ... + 49970457.

It is an arithmetic number, because the mean of its divisors is an integer number (824504772).

Almost surely, 2^81000797787 is an apocalyptic number.

81000797787 is a deficient number, since it is larger than the sum of its proper divisors (77304118437).

81000797787 is a wasteful number, since it uses less digits than its factorization.

81000797787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1798 (or 1795 counting only the distinct ones).

The product of its (nonzero) digits is 1382976, while the sum is 54.

The spelling of 81000797787 in words is "eighty-one billion, seven hundred ninety-seven thousand, seven hundred eighty-seven".