12455821 has 4 divisors (see below), whose sum is σ = 14235232. Its totient is φ = 10676412.

The previous prime is 12455813. The next prime is 12455837. The reversal of 12455821 is 12855421.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12855421 = 31 ⋅414691.

It is a cyclic number.

It is not a de Polignac number, because 12455821 - 2³ = 12455813 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12455821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12455801) 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, 889695 + ... + 889708.

It is an arithmetic number, because the mean of its divisors is an integer number (3558808).

Almost surely, 2^12455821 is an apocalyptic number.

It is an amenable number.

12455821 is a deficient number, since it is larger than the sum of its proper divisors (1779411).

12455821 is an equidigital number, since it uses as much as digits as its factorization.

12455821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1779410.

The product of its digits is 3200, while the sum is 28.

The square root of 12455821 is about 3529.2805215794. The cubic root of 12455821 is about 231.8057045980.

It can be divided in two parts, 124 and 55821, that added together give a triangular number (55945 = T₃₃₄).

The spelling of 12455821 in words is "twelve million, four hundred fifty-five thousand, eight hundred twenty-one".