9991254123 has 16 divisors (see below), whose sum is σ = 14890498560. Its totient is φ = 6620947848.

The previous prime is 9991254113. The next prime is 9991254157. The reversal of 9991254123 is 3214521999.

9991254123 is a `hidden beast` number, since 9 + 99 + 12 + 541 + 2 + 3 = 666.

It is not a de Polignac number, because 9991254123 - 2⁹ = 9991253611 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9991254113) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1103415 + ... + 1112432.

It is an arithmetic number, because the mean of its divisors is an integer number (930656160).

Almost surely, 2^9991254123 is an apocalyptic number.

9991254123 is a deficient number, since it is larger than the sum of its proper divisors (4899244437).

9991254123 is a wasteful number, since it uses less digits than its factorization.

9991254123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2216023 (or 2216017 counting only the distinct ones).

The product of its digits is 174960, while the sum is 45.

The square root of 9991254123 is about 99956.2610495211. The cubic root of 9991254123 is about 2153.8064261455.

The spelling of 9991254123 in words is "nine billion, nine hundred ninety-one million, two hundred fifty-four thousand, one hundred twenty-three".