12784021 has 4 divisors (see below), whose sum is σ = 13339872. Its totient is φ = 12228172.

The previous prime is 12784007. The next prime is 12784033. The reversal of 12784021 is 12048721.

It is a happy number.

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: 12048721 = 1721 ⋅7001.

It is a cyclic number.

It is not a de Polignac number, because 12784021 - 2¹⁵ = 12751253 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 (12784091) 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, 277891 + ... + 277936.

It is an arithmetic number, because the mean of its divisors is an integer number (3334968).

Almost surely, 2^12784021 is an apocalyptic number.

It is an amenable number.

12784021 is a deficient number, since it is larger than the sum of its proper divisors (555851).

12784021 is an equidigital number, since it uses as much as digits as its factorization.

12784021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555850.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 12784021 is about 3575.4749334879. The cubic root of 12784021 is about 233.8240391919.

It can be divided in two parts, 127 and 84021, that added together give a palindrome (84148).

The spelling of 12784021 in words is "twelve million, seven hundred eighty-four thousand, twenty-one".