1151991 has 12 divisors (see below), whose sum is σ = 1718080. Its totient is φ = 743040.

The previous prime is 1151987. The next prime is 1151993. The reversal of 1151991 is 1991511.

It is not a de Polignac number, because 1151991 - 2² = 1151987 is a prime.

It is a Duffinian number.

1151991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1151993) 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 11 ways as a sum of consecutive naturals, for example, 1786 + ... + 2343.

2^1151991 is an apocalyptic number.

1151991 is a deficient number, since it is larger than the sum of its proper divisors (566089).

1151991 is a wasteful number, since it uses less digits than its factorization.

1151991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4166 (or 4163 counting only the distinct ones).

The product of its digits is 405, while the sum is 27.

The square root of 1151991 is about 1073.3084365643. The cubic root of 1151991 is about 104.8293827737.

The spelling of 1151991 in words is "one million, one hundred fifty-one thousand, nine hundred ninety-one".