12777649021 has 4 divisors (see below), whose sum is σ = 13529275452. Its totient is φ = 12026022592.

The previous prime is 12777649019. The next prime is 12777649063. The reversal of 12777649021 is 12094677721.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6338388996 + 6439260025 = 79614^2 + 80245^2 .

It is a cyclic number.

It is not a de Polignac number, because 12777649021 - 2¹ = 12777649019 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 (12777649091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 375813190 + ... + 375813223.

It is an arithmetic number, because the mean of its divisors is an integer number (3382318863).

Almost surely, 2^12777649021 is an apocalyptic number.

It is an amenable number.

12777649021 is a deficient number, since it is larger than the sum of its proper divisors (751626431).

12777649021 is an equidigital number, since it uses as much as digits as its factorization.

12777649021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751626430.

The product of its (nonzero) digits is 296352, while the sum is 46.

The spelling of 12777649021 in words is "twelve billion, seven hundred seventy-seven million, six hundred forty-nine thousand, twenty-one".