12106721 has 4 divisors (see below), whose sum is σ = 13207344. Its totient is φ = 11006100.

The previous prime is 12106711. The next prime is 12106789. The reversal of 12106721 is 12760121.

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 a cyclic number.

It is not a de Polignac number, because 12106721 - 2⁶ = 12106657 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12106693 and 12106702.

It is not an unprimeable number, because it can be changed into a prime (12106711) 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, 550295 + ... + 550316.

It is an arithmetic number, because the mean of its divisors is an integer number (3301836).

Almost surely, 2^12106721 is an apocalyptic number.

12106721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12106721 is a deficient number, since it is larger than the sum of its proper divisors (1100623).

12106721 is a wasteful number, since it uses less digits than its factorization.

12106721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1100622.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 12106721 is about 3479.4713678948. The cubic root of 12106721 is about 229.6195411361.

Adding to 12106721 its reverse (12760121), we get a palindrome (24866842).

The spelling of 12106721 in words is "twelve million, one hundred six thousand, seven hundred twenty-one".