3977944154621 has 2 divisors, whose sum is σ = 3977944154622. Its totient is φ = 3977944154620.

The previous prime is 3977944154557. The next prime is 3977944154629. The reversal of 3977944154621 is 1264514497793.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3396332011396 + 581612143225 = 1842914^2 + 762635^2 .

It is an emirp because it is prime and its reverse (1264514497793) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3977944154621 - 2⁶ = 3977944154557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3977944154629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1988972077310 + 1988972077311.

It is an arithmetic number, because the mean of its divisors is an integer number (1988972077311).

Almost surely, 2^{3977944154621} is an apocalyptic number.

It is an amenable number.

3977944154621 is a deficient number, since it is larger than the sum of its proper divisors (1).

3977944154621 is an equidigital number, since it uses as much as digits as its factorization.

3977944154621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45722880, while the sum is 62.

The spelling of 3977944154621 in words is "three trillion, nine hundred seventy-seven billion, nine hundred forty-four million, one hundred fifty-four thousand, six hundred twenty-one".