389681681 has 2 divisors, whose sum is σ = 389681682. Its totient is φ = 389681680.

The previous prime is 389681629. The next prime is 389681683. The reversal of 389681681 is 186186983.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 286151056 + 103530625 = 16916^2 + 10175^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-389681681 is a prime.

It is a super-2 number, since 2×389681681² = 303703625013971522, which contains 22 as substring.

Together with 389681683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (389681683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 194840840 + 194840841.

It is an arithmetic number, because the mean of its divisors is an integer number (194840841).

Almost surely, 2^389681681 is an apocalyptic number.

It is an amenable number.

389681681 is a deficient number, since it is larger than the sum of its proper divisors (1).

389681681 is an equidigital number, since it uses as much as digits as its factorization.

389681681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 497664, while the sum is 50.

The square root of 389681681 is about 19740.3566583788. The cubic root of 389681681 is about 730.4155268638.

The spelling of 389681681 in words is "three hundred eighty-nine million, six hundred eighty-one thousand, six hundred eighty-one".