81117976607 has 4 divisors (see below), whose sum is σ = 82229181840. Its totient is φ = 80006771376.

The previous prime is 81117976579. The next prime is 81117976631. The reversal of 81117976607 is 70667971118.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70667971118 = 2 ⋅35333985559.

It is a cyclic number.

It is not a de Polignac number, because 81117976607 - 2²⁰ = 81116928031 is a prime.

It is a super-2 number, since 2×81117976607² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81117976507) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 555602507 + ... + 555602652.

It is an arithmetic number, because the mean of its divisors is an integer number (20557295460).

Almost surely, 2^81117976607 is an apocalyptic number.

81117976607 is a deficient number, since it is larger than the sum of its proper divisors (1111205233).

81117976607 is a wasteful number, since it uses less digits than its factorization.

81117976607 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1111205232.

The product of its (nonzero) digits is 889056, while the sum is 53.

The spelling of 81117976607 in words is "eighty-one billion, one hundred seventeen million, nine hundred seventy-six thousand, six hundred seven".