991204207 has 4 divisors (see below), whose sum is σ = 1132804816. Its totient is φ = 849603600.

The previous prime is 991204187. The next prime is 991204213. The reversal of 991204207 is 702402199.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 702402199 = 4409 ⋅159311.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991204207 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991244207) 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, 70800294 + ... + 70800307.

It is an arithmetic number, because the mean of its divisors is an integer number (283201204).

Almost surely, 2^991204207 is an apocalyptic number.

991204207 is a deficient number, since it is larger than the sum of its proper divisors (141600609).

991204207 is a wasteful number, since it uses less digits than its factorization.

991204207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141600608.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 991204207 is about 31483.3957348949. The cubic root of 991204207 is about 997.0594305268.

The spelling of 991204207 in words is "nine hundred ninety-one million, two hundred four thousand, two hundred seven".