12840661 has 4 divisors (see below), whose sum is σ = 13596012. Its totient is φ = 12085312.

The previous prime is 12840643. The next prime is 12840677. The reversal of 12840661 is 16604821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3538161 + 9302500 = 1881^2 + 3050^2 .

It is a cyclic number.

It is not a de Polignac number, because 12840661 - 2¹¹ = 12838613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12840631) 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, 377650 + ... + 377683.

It is an arithmetic number, because the mean of its divisors is an integer number (3399003).

Almost surely, 2^12840661 is an apocalyptic number.

It is an amenable number.

12840661 is a deficient number, since it is larger than the sum of its proper divisors (755351).

12840661 is an equidigital number, since it uses as much as digits as its factorization.

12840661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 755350.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 12840661 is about 3583.3868058026. The cubic root of 12840661 is about 234.1688520008.

The spelling of 12840661 in words is "twelve million, eight hundred forty thousand, six hundred sixty-one".