81916610787 has 12 divisors (see below), whose sum is σ = 129080720184. Its totient is φ = 49646430720.

The previous prime is 81916610701. The next prime is 81916610801. The reversal of 81916610787 is 78701661918.

81916610787 is a `hidden beast` number, since 8 + 1 + 9 + 16 + 610 + 7 + 8 + 7 = 666.

It is not a de Polignac number, because 81916610787 - 2¹⁰ = 81916609763 is a prime.

It is a super-2 number, since 2×81916610787² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81916610987) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 413720158 + ... + 413720355.

It is an arithmetic number, because the mean of its divisors is an integer number (10756726682).

Almost surely, 2^81916610787 is an apocalyptic number.

81916610787 is a deficient number, since it is larger than the sum of its proper divisors (47164109397).

81916610787 is a wasteful number, since it uses less digits than its factorization.

81916610787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 827440530 (or 827440527 counting only the distinct ones).

The product of its (nonzero) digits is 1016064, while the sum is 54.

The spelling of 81916610787 in words is "eighty-one billion, nine hundred sixteen million, six hundred ten thousand, seven hundred eighty-seven".