81868689778 has 8 divisors (see below), whose sum is σ = 123489085680. Its totient is φ = 40705661220.

The previous prime is 81868689757. The next prime is 81868689779. The reversal of 81868689778 is 87798686818.

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

It is not an unprimeable number, because it can be changed into a prime (81868689779) 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, 114341388 + ... + 114342103.

It is an arithmetic number, because the mean of its divisors is an integer number (15436135710).

Almost surely, 2^81868689778 is an apocalyptic number.

81868689778 is a deficient number, since it is larger than the sum of its proper divisors (41620395902).

81868689778 is a wasteful number, since it uses less digits than its factorization.

81868689778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228683672.

The product of its digits is 520224768, while the sum is 76.

The spelling of 81868689778 in words is "eighty-one billion, eight hundred sixty-eight million, six hundred eighty-nine thousand, seven hundred seventy-eight".