12291681 has 4 divisors (see below), whose sum is σ = 16388912. Its totient is φ = 8194452.

The previous prime is 12291673. The next prime is 12291691. The reversal of 12291681 is 18619221.

It is a happy number.

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 12291681 - 2³ = 12291673 is a prime.

It is a super-2 number, since 2×12291681² = 302170843611522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12291641) 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, 2048611 + ... + 2048616.

It is an arithmetic number, because the mean of its divisors is an integer number (4097228).

Almost surely, 2^12291681 is an apocalyptic number.

It is an amenable number.

12291681 is a deficient number, since it is larger than the sum of its proper divisors (4097231).

12291681 is an equidigital number, since it uses as much as digits as its factorization.

12291681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4097230.

The product of its digits is 1728, while the sum is 30.

The square root of 12291681 is about 3505.9493721387. The cubic root of 12291681 is about 230.7829711391.

The spelling of 12291681 in words is "twelve million, two hundred ninety-one thousand, six hundred eighty-one".