12421778 has 4 divisors (see below), whose sum is σ = 18632670. Its totient is φ = 6210888.

The previous prime is 12421757. The next prime is 12421789. The reversal of 12421778 is 87712421.

It is a happy number.

12421778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in only one way, i.e., 7656289 + 4765489 = 2767^2 + 2183^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3105443 + ... + 3105446.

Almost surely, 2^12421778 is an apocalyptic number.

12421778 is a deficient number, since it is larger than the sum of its proper divisors (6210892).

12421778 is an equidigital number, since it uses as much as digits as its factorization.

12421778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6210891.

The product of its digits is 6272, while the sum is 32.

The square root of 12421778 is about 3524.4542839992. The cubic root of 12421778 is about 231.5943292143.

The spelling of 12421778 in words is "twelve million, four hundred twenty-one thousand, seven hundred seventy-eight".