1156989 has 4 divisors (see below), whose sum is σ = 1542656. Its totient is φ = 771324.

The previous prime is 1156963. The next prime is 1156997. The reversal of 1156989 is 9896511.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1156989 - 2¹⁷ = 1025917 is a prime.

It is a super-2 number, since 2×1156989² = 2677247092242, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1156949) 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 3 ways as a sum of consecutive naturals, for example, 192829 + ... + 192834.

It is an arithmetic number, because the mean of its divisors is an integer number (385664).

2^1156989 is an apocalyptic number.

It is an amenable number.

1156989 is a deficient number, since it is larger than the sum of its proper divisors (385667).

1156989 is an equidigital number, since it uses as much as digits as its factorization.

1156989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385666.

The product of its digits is 19440, while the sum is 39.

The square root of 1156989 is about 1075.6342315118. The cubic root of 1156989 is about 104.9807674525.

It can be divided in two parts, 1156 and 989, that added together give a triangular number (2145 = T₆₅).

The spelling of 1156989 in words is "one million, one hundred fifty-six thousand, nine hundred eighty-nine".