12777721 has 6 divisors (see below), whose sum is σ = 14045066. Its totient is φ = 11616000.

The previous prime is 12777703. The next prime is 12777763.

12777721 is nontrivially palindromic in base 10.

12777721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 12702096 + 75625 = 3564^2 + 275^2 .

It is not a de Polignac number, because 12777721 - 2⁹ = 12777209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12777781) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 52680 + ... + 52921.

Almost surely, 2^12777721 is an apocalyptic number.

12777721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12777721 is a deficient number, since it is larger than the sum of its proper divisors (1267345).

12777721 is a wasteful number, since it uses less digits than its factorization.

12777721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105623 (or 105612 counting only the distinct ones).

The product of its digits is 9604, while the sum is 34.

The square root of 12777721 is about 3574.5938230798. The cubic root of 12777721 is about 233.7856231752.

It can be divided in two parts, 1277 and 7721, that added together give a palindrome (8998).

The spelling of 12777721 in words is "twelve million, seven hundred seventy-seven thousand, seven hundred twenty-one".