9891218923 has 2 divisors, whose sum is σ = 9891218924. Its totient is φ = 9891218922.

The previous prime is 9891218837. The next prime is 9891218929. The reversal of 9891218923 is 3298121989.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 9891218923 - 2⁹ = 9891218411 is a prime.

It is not a weakly prime, because it can be changed into another prime (9891218929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4945609461 + 4945609462.

It is an arithmetic number, because the mean of its divisors is an integer number (4945609462).

Almost surely, 2^9891218923 is an apocalyptic number.

9891218923 is a deficient number, since it is larger than the sum of its proper divisors (1).

9891218923 is an equidigital number, since it uses as much as digits as its factorization.

9891218923 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 559872, while the sum is 52.

The square root of 9891218923 is about 99454.6073492827. The cubic root of 9891218923 is about 2146.5941332591.

The spelling of 9891218923 in words is "nine billion, eight hundred ninety-one million, two hundred eighteen thousand, nine hundred twenty-three".