11578921 has 4 divisors (see below), whose sum is σ = 12260052. Its totient is φ = 10897792.

The previous prime is 11578909. The next prime is 11578949. The reversal of 11578921 is 12987511.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12987511 = 157 ⋅82723.

It can be written as a sum of positive squares in 2 ways, for example, as 4999696 + 6579225 = 2236^2 + 2565^2 .

It is a cyclic number.

It is not a de Polignac number, because 11578921 - 2¹³ = 11570729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11578901) 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 in 3 ways as a sum of consecutive naturals, for example, 340540 + ... + 340573.

It is an arithmetic number, because the mean of its divisors is an integer number (3065013).

Almost surely, 2^11578921 is an apocalyptic number.

It is an amenable number.

11578921 is a deficient number, since it is larger than the sum of its proper divisors (681131).

11578921 is an equidigital number, since it uses as much as digits as its factorization.

11578921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 681130.

The product of its digits is 5040, while the sum is 34.

The square root of 11578921 is about 3402.7813623564. The cubic root of 11578921 is about 226.2330394376.

The spelling of 11578921 in words is "eleven million, five hundred seventy-eight thousand, nine hundred twenty-one".