991212499 has 4 divisors (see below), whose sum is σ = 1018002064. Its totient is φ = 964422936.

The previous prime is 991212493. The next prime is 991212503. The reversal of 991212499 is 994212199.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 994212199 = 811 ⋅1225909.

It is a cyclic number.

It is not a de Polignac number, because 991212499 - 2⁹ = 991211987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991212493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13394727 + ... + 13394800.

It is an arithmetic number, because the mean of its divisors is an integer number (254500516).

Almost surely, 2^991212499 is an apocalyptic number.

991212499 is a deficient number, since it is larger than the sum of its proper divisors (26789565).

991212499 is a wasteful number, since it uses less digits than its factorization.

991212499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26789564.

The product of its digits is 104976, while the sum is 46.

The square root of 991212499 is about 31483.5274230827. The cubic root of 991212499 is about 997.0622108465.

The spelling of 991212499 in words is "nine hundred ninety-one million, two hundred twelve thousand, four hundred ninety-nine".