81878858981 has 8 divisors (see below), whose sum is σ = 84185420928. Its totient is φ = 79587036000.

The previous prime is 81878858953. The next prime is 81878858983. The reversal of 81878858981 is 18985887818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81878858981 - 2²⁶ = 81811750117 is a prime.

It is a super-2 number, since 2×81878858981² (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 (81878858983) 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 7 ways as a sum of consecutive naturals, for example, 3673475 + ... + 3695696.

It is an arithmetic number, because the mean of its divisors is an integer number (10523177616).

Almost surely, 2^81878858981 is an apocalyptic number.

It is an amenable number.

81878858981 is a deficient number, since it is larger than the sum of its proper divisors (2306561947).

81878858981 is a wasteful number, since it uses less digits than its factorization.

81878858981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7369483.

The product of its digits is 82575360, while the sum is 71.

The spelling of 81878858981 in words is "eighty-one billion, eight hundred seventy-eight million, eight hundred fifty-eight thousand, nine hundred eighty-one".