12261821 has 16 divisors (see below), whose sum is σ = 15167040. Its totient is φ = 9745920.

The previous prime is 12261817. The next prime is 12261889. The reversal of 12261821 is 12816221.

It is a cyclic number.

It is not a de Polignac number, because 12261821 - 2² = 12261817 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12261521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 461 + ... + 4973.

It is an arithmetic number, because the mean of its divisors is an integer number (947940).

Almost surely, 2^12261821 is an apocalyptic number.

12261821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12261821 is a deficient number, since it is larger than the sum of its proper divisors (2905219).

12261821 is a wasteful number, since it uses less digits than its factorization.

12261821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4556.

The product of its digits is 384, while the sum is 23.

The square root of 12261821 is about 3501.6883070885. The cubic root of 12261821 is about 230.5959403803.

The spelling of 12261821 in words is "twelve million, two hundred sixty-one thousand, eight hundred twenty-one".