991964 has 6 divisors (see below), whose sum is σ = 1735944. Its totient is φ = 495980.

The previous prime is 991961. The next prime is 991973. The reversal of 991964 is 469199.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991964.

It is not an unprimeable number, because it can be changed into a prime (991961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123992 + ... + 123999.

It is an arithmetic number, because the mean of its divisors is an integer number (289324).

2⁹⁹¹⁹⁶⁴ is an apocalyptic number.

It is an amenable number.

991964 is a deficient number, since it is larger than the sum of its proper divisors (743980).

991964 is a wasteful number, since it uses less digits than its factorization.

991964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247995 (or 247993 counting only the distinct ones).

The product of its digits is 17496, while the sum is 38.

The square root of 991964 is about 995.9738952402. The cubic root of 991964 is about 99.7314125872.

The spelling of 991964 in words is "nine hundred ninety-one thousand, nine hundred sixty-four".