681669 has 8 divisors (see below), whose sum is σ = 1009920. Its totient is φ = 454428.

The previous prime is 681647. The next prime is 681673. The reversal of 681669 is 966186.

681669 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a de Polignac number, because none of the positive numbers 2^k-681669 is a prime.

It is a super-2 number, since 2×681669² = 929345251122, which contains 22 as substring.

681669 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12597 + ... + 12650.

It is an arithmetic number, because the mean of its divisors is an integer number (126240).

2⁶⁸¹⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

681669 is a deficient number, since it is larger than the sum of its proper divisors (328251).

681669 is a wasteful number, since it uses less digits than its factorization.

681669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25256 (or 25250 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 681669 is about 825.6324848260. The cubic root of 681669 is about 88.0084788662.

The spelling of 681669 in words is "six hundred eighty-one thousand, six hundred sixty-nine".