991361143 has 16 divisors (see below), whose sum is σ = 1043228160. Its totient is φ = 940760800.

The previous prime is 991361113. The next prime is 991361149. The reversal of 991361143 is 341163199.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991361143 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 (991361149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 961038 + ... + 962068.

It is an arithmetic number, because the mean of its divisors is an integer number (65201760).

Almost surely, 2^991361143 is an apocalyptic number.

991361143 is a deficient number, since it is larger than the sum of its proper divisors (51867017).

991361143 is a wasteful number, since it uses less digits than its factorization.

With its successor (991361144) it forms an eRAP, since the sums of their prime factors are consecutive (1598 and 1599).

991361143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1598.

The product of its digits is 17496, while the sum is 37.

The square root of 991361143 is about 31485.8879976411. The cubic root of 991361143 is about 997.1120487664.

The spelling of 991361143 in words is "nine hundred ninety-one million, three hundred sixty-one thousand, one hundred forty-three".