9891218897 has 16 divisors (see below), whose sum is σ = 11344440960. Its totient is φ = 8448104832.

The previous prime is 9891218837. The next prime is 9891218923. The reversal of 9891218897 is 7988121989.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9891218897 is a prime.

It is a super-2 number, since 2×9891218897² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9891218807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2598998 + ... + 2602800.

It is an arithmetic number, because the mean of its divisors is an integer number (709027560).

Almost surely, 2^9891218897 is an apocalyptic number.

It is an amenable number.

9891218897 is a deficient number, since it is larger than the sum of its proper divisors (1453222063).

9891218897 is a wasteful number, since it uses less digits than its factorization.

9891218897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5032.

The product of its digits is 5225472, while the sum is 62.

The square root of 9891218897 is about 99454.6072185698. The cubic root of 9891218897 is about 2146.5941313783.

The spelling of 9891218897 in words is "nine billion, eight hundred ninety-one million, two hundred eighteen thousand, eight hundred ninety-seven".