12170721 has 8 divisors (see below), whose sum is σ = 16327840. Its totient is φ = 8063712.

The previous prime is 12170713. The next prime is 12170771. The reversal of 12170721 is 12707121.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 12170721 - 2³ = 12170713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12170771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11956 + ... + 12933.

It is an arithmetic number, because the mean of its divisors is an integer number (2040980).

Almost surely, 2^12170721 is an apocalyptic number.

It is an amenable number.

12170721 is a deficient number, since it is larger than the sum of its proper divisors (4157119).

12170721 is a wasteful number, since it uses less digits than its factorization.

12170721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25055.

The product of its (nonzero) digits is 196, while the sum is 21.

The square root of 12170721 is about 3488.6560449548. The cubic root of 12170721 is about 230.0234443651.

Adding to 12170721 its reverse (12707121), we get a palindrome (24877842).

The spelling of 12170721 in words is "twelve million, one hundred seventy thousand, seven hundred twenty-one".