991207987 has 8 divisors (see below), whose sum is σ = 1235791872. Its totient is φ = 772369800.

The previous prime is 991207939. The next prime is 991207991. The reversal of 991207987 is 789702199.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 991207987 - 2¹¹ = 991205939 is a prime.

It is not an unprimeable number, because it can be changed into a prime (991207927) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6436339 + ... + 6436492.

It is an arithmetic number, because the mean of its divisors is an integer number (154473984).

Almost surely, 2^991207987 is an apocalyptic number.

991207987 is a deficient number, since it is larger than the sum of its proper divisors (244583885).

991207987 is a wasteful number, since it uses less digits than its factorization.

991207987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12872849.

The product of its (nonzero) digits is 571536, while the sum is 52.

The square root of 991207987 is about 31483.4557664815. The cubic root of 991207987 is about 997.0606979683.

The spelling of 991207987 in words is "nine hundred ninety-one million, two hundred seven thousand, nine hundred eighty-seven".