12377821 has 4 divisors (see below), whose sum is σ = 12407644. Its totient is φ = 12348000.

The previous prime is 12377791. The next prime is 12377843. The reversal of 12377821 is 12877321.

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 509796 + 11868025 = 714^2 + 3445^2 .

It is a 3-Lehmer number, since φ(12377821) divides (12377821-1)³.

It is a cyclic number.

It is not a de Polignac number, because 12377821 - 2⁵ = 12377789 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 (12377861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14280 + ... + 15121.

It is an arithmetic number, because the mean of its divisors is an integer number (3101911).

Almost surely, 2^12377821 is an apocalyptic number.

It is an amenable number.

12377821 is a deficient number, since it is larger than the sum of its proper divisors (29823).

12377821 is an equidigital number, since it uses as much as digits as its factorization.

12377821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29822.

The product of its digits is 4704, while the sum is 31.

The square root of 12377821 is about 3518.2127565001. The cubic root of 12377821 is about 231.3208250556.

Subtracting 12377821 from its reverse (12877321), we obtain a triangular number (499500 = T₉₉₉).

The spelling of 12377821 in words is "twelve million, three hundred seventy-seven thousand, eight hundred twenty-one".