1604168681 has 2 divisors, whose sum is σ = 1604168682. Its totient is φ = 1604168680.

The previous prime is 1604168627. The next prime is 1604168701. The reversal of 1604168681 is 1868614061.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1564993600 + 39175081 = 39560^2 + 6259^2 .

It is an emirp because it is prime and its reverse (1868614061) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1604168681 - 2²² = 1599974377 is a prime.

It is a super-2 number, since 2×1604168681² = 5146714314202559522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1604158681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802084340 + 802084341.

It is an arithmetic number, because the mean of its divisors is an integer number (802084341).

Almost surely, 2^1604168681 is an apocalyptic number.

It is an amenable number.

1604168681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1604168681 is an equidigital number, since it uses as much as digits as its factorization.

1604168681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 55296, while the sum is 41.

The square root of 1604168681 is about 40052.0746154303. The cubic root of 1604168681 is about 1170.6219891504.

The spelling of 1604168681 in words is "one billion, six hundred four million, one hundred sixty-eight thousand, six hundred eighty-one".