998961791 has 4 divisors (see below), whose sum is σ = 1005577584. Its totient is φ = 992346000.

The previous prime is 998961787. The next prime is 998961793. The reversal of 998961791 is 197169899.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 197169899 = 3251 ⋅60649.

It is a cyclic number.

It is not a de Polignac number, because 998961791 - 2² = 998961787 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 998961791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (998961793) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3307670 + ... + 3307971.

It is an arithmetic number, because the mean of its divisors is an integer number (251394396).

Almost surely, 2^998961791 is an apocalyptic number.

998961791 is a deficient number, since it is larger than the sum of its proper divisors (6615793).

998961791 is a wasteful number, since it uses less digits than its factorization.

998961791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6615792.

The product of its digits is 2204496, while the sum is 59.

The square root of 998961791 is about 31606.3568131476. The cubic root of 998961791 is about 999.6538105000.

The spelling of 998961791 in words is "nine hundred ninety-eight million, nine hundred sixty-one thousand, seven hundred ninety-one".