3977649395891 has 4 divisors (see below), whose sum is σ = 4018656090792. Its totient is φ = 3936642700992.

The previous prime is 3977649395861. The next prime is 3977649395939. The reversal of 3977649395891 is 1985939467793.

3977649395891 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 is a cyclic number.

It is not a de Polignac number, because 3977649395891 - 2¹⁰ = 3977649394867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3977649395831) 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, 20503347305 + ... + 20503347498.

It is an arithmetic number, because the mean of its divisors is an integer number (1004664022698).

Almost surely, 2^{3977649395891} is an apocalyptic number.

3977649395891 is a deficient number, since it is larger than the sum of its proper divisors (41006694901).

3977649395891 is an equidigital number, since it uses as much as digits as its factorization.

3977649395891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41006694900.

The product of its digits is 2777664960, while the sum is 80.

The spelling of 3977649395891 in words is "three trillion, nine hundred seventy-seven billion, six hundred forty-nine million, three hundred ninety-five thousand, eight hundred ninety-one".