681208169 has 2 divisors, whose sum is σ = 681208170. Its totient is φ = 681208168.

The previous prime is 681208163. The next prime is 681208189. The reversal of 681208169 is 961802186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 577921600 + 103286569 = 24040^2 + 10163^2 .

It is a cyclic number.

It is not a de Polignac number, because 681208169 - 2⁸ = 681207913 is a prime.

It is a super-2 number, since 2×681208169² = 928089139024665122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (681208163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340604084 + 340604085.

It is an arithmetic number, because the mean of its divisors is an integer number (340604085).

Almost surely, 2^681208169 is an apocalyptic number.

It is an amenable number.

681208169 is a deficient number, since it is larger than the sum of its proper divisors (1).

681208169 is an equidigital number, since it uses as much as digits as its factorization.

681208169 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 681208169 is about 26099.9649233481. The cubic root of 681208169 is about 879.8864217224.

The spelling of 681208169 in words is "six hundred eighty-one million, two hundred eight thousand, one hundred sixty-nine".