389778021641 has 2 divisors, whose sum is σ = 389778021642. Its totient is φ = 389778021640.

The previous prime is 389778021629. The next prime is 389778021649. The reversal of 389778021641 is 146120877983.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 275935887616 + 113842134025 = 525296^2 + 337405^2 .

It is an emirp because it is prime and its reverse (146120877983) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-389778021641 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (389778021649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 194889010820 + 194889010821.

It is an arithmetic number, because the mean of its divisors is an integer number (194889010821).

Almost surely, 2^389778021641 is an apocalyptic number.

It is an amenable number.

389778021641 is a deficient number, since it is larger than the sum of its proper divisors (1).

389778021641 is an equidigital number, since it uses as much as digits as its factorization.

389778021641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4064256, while the sum is 56.

The spelling of 389778021641 in words is "three hundred eighty-nine billion, seven hundred seventy-eight million, twenty-one thousand, six hundred forty-one".