1158721 has 4 divisors (see below), whose sum is σ = 1185712. Its totient is φ = 1131732.

The previous prime is 1158719. The next prime is 1158743. The reversal of 1158721 is 1278511.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1278511 = 13 ⋅98347.

It is a cyclic number.

It is not a de Polignac number, because 1158721 - 2¹ = 1158719 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (1158761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13431 + ... + 13516.

It is an arithmetic number, because the mean of its divisors is an integer number (296428).

2^1158721 is an apocalyptic number.

It is an amenable number.

1158721 is a deficient number, since it is larger than the sum of its proper divisors (26991).

1158721 is an equidigital number, since it uses as much as digits as its factorization.

1158721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26990.

The product of its digits is 560, while the sum is 25.

The square root of 1158721 is about 1076.4390368247. The cubic root of 1158721 is about 105.0331263582.

It can be divided in two parts, 115 and 8721, that added together give a square (8836 = 94²).

The spelling of 1158721 in words is "one million, one hundred fifty-eight thousand, seven hundred twenty-one".