991173898035 has 24 divisors (see below), whose sum is σ = 1808457640080. Its totient is φ = 500803653312.

The previous prime is 991173898021. The next prime is 991173898049. The reversal of 991173898035 is 530898371199.

It is an interprime number because it is at equal distance from previous prime (991173898021) and next prime (991173898049).

It is not a de Polignac number, because 991173898035 - 2⁵ = 991173898003 is a prime.

It is a super-2 number, since 2×991173898035² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 579633004 + ... + 579634713.

It is an arithmetic number, because the mean of its divisors is an integer number (75352401670).

Almost surely, 2^991173898035 is an apocalyptic number.

991173898035 is a gapful number since it is divisible by the number (95) formed by its first and last digit.

991173898035 is a deficient number, since it is larger than the sum of its proper divisors (817283742045).

991173898035 is a wasteful number, since it uses less digits than its factorization.

991173898035 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1159267747 (or 1159267744 counting only the distinct ones).

The product of its (nonzero) digits is 14696640, while the sum is 63.

The spelling of 991173898035 in words is "nine hundred ninety-one billion, one hundred seventy-three million, eight hundred ninety-eight thousand, thirty-five".