1199991 has 16 divisors (see below), whose sum is σ = 1784160. Its totient is φ = 712320.

The previous prime is 1199969. The next prime is 1199993. The reversal of 1199991 is 1999911.

It is not a de Polignac number, because 1199991 - 2¹⁴ = 1183607 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an Ulam number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1199993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 601 + ... + 1661.

It is an arithmetic number, because the mean of its divisors is an integer number (111510).

2^1199991 is an apocalyptic number.

1199991 is a deficient number, since it is larger than the sum of its proper divisors (584169).

1199991 is a wasteful number, since it uses less digits than its factorization.

1199991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1106.

The product of its digits is 6561, while the sum is 39.

The square root of 1199991 is about 1095.4410070834. The cubic root of 1199991 is about 106.2655912530.

It can be divided in two parts, 11999 and 91, that added together give a triangular number (12090 = T₁₅₅).

The spelling of 1199991 in words is "one million, one hundred ninety-nine thousand, nine hundred ninety-one".