12777921 has 36 divisors (see below), whose sum is σ = 20706816. Its totient is φ = 7581600.

The previous prime is 12777917. The next prime is 12777943. The reversal of 12777921 is 12977721.

12777921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12777921 - 2² = 12777917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12777901) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 47016 + ... + 47286.

Almost surely, 2^12777921 is an apocalyptic number.

It is an amenable number.

12777921 is a deficient number, since it is larger than the sum of its proper divisors (7928895).

12777921 is a wasteful number, since it uses less digits than its factorization.

12777921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334 (or 318 counting only the distinct ones).

The product of its digits is 12348, while the sum is 36.

The square root of 12777921 is about 3574.6217981767. The cubic root of 12777921 is about 233.7868429253.

The spelling of 12777921 in words is "twelve million, seven hundred seventy-seven thousand, nine hundred twenty-one".