9891218678 has 16 divisors (see below), whose sum is σ = 16889354496. Its totient is φ = 4300529640.

The previous prime is 9891218657. The next prime is 9891218693. The reversal of 9891218678 is 8768121989.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9773426 + ... + 9774437.

It is an arithmetic number, because the mean of its divisors is an integer number (1055584656).

Almost surely, 2^9891218678 is an apocalyptic number.

9891218678 is a deficient number, since it is larger than the sum of its proper divisors (6998135818).

9891218678 is a wasteful number, since it uses less digits than its factorization.

9891218678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19547899.

The product of its digits is 3483648, while the sum is 59.

The square root of 9891218678 is about 99454.6061175650. The cubic root of 9891218678 is about 2146.5941155358.

It can be divided in two parts, 989121 and 8678, that added together give a palindrome (997799).

The spelling of 9891218678 in words is "nine billion, eight hundred ninety-one million, two hundred eighteen thousand, six hundred seventy-eight".