991916402499 has 48 divisors (see below), whose sum is σ = 1615481925120. Its totient is φ = 601072124400.

The previous prime is 991916402473. The next prime is 991916402567. The reversal of 991916402499 is 994204619199.

991916402499 is a `hidden beast` number, since 9 + 91 + 9 + 16 + 40 + 2 + 499 = 666.

It is a Cunningham number, because it is equal to 995950²-1.

It is not a de Polignac number, because 991916402499 - 2¹¹ = 991916400451 is a prime.

It is not an unprimeable number, because it can be changed into a prime (991916407499) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 26872234 + ... + 26909120.

It is an arithmetic number, because the mean of its divisors is an integer number (33655873440).

Almost surely, 2^991916402499 is an apocalyptic number.

991916402499 is a gapful number since it is divisible by the number (99) formed by its first and last digit.

991916402499 is a deficient number, since it is larger than the sum of its proper divisors (623565522621).

991916402499 is a wasteful number, since it uses less digits than its factorization.

991916402499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45149 (or 45132 counting only the distinct ones).

The product of its (nonzero) digits is 11337408, while the sum is 63.

The spelling of 991916402499 in words is "nine hundred ninety-one billion, nine hundred sixteen million, four hundred two thousand, four hundred ninety-nine".