681399 has 8 divisors (see below), whose sum is σ = 1009520. Its totient is φ = 454248.

The previous prime is 681371. The next prime is 681403. The reversal of 681399 is 993186.

It is not a de Polignac number, because 681399 - 2⁵ = 681367 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 681399.

It is not an unprimeable number, because it can be changed into a prime (681899) 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, 12592 + ... + 12645.

It is an arithmetic number, because the mean of its divisors is an integer number (126190).

2⁶⁸¹³⁹⁹ is an apocalyptic number.

681399 is a deficient number, since it is larger than the sum of its proper divisors (328121).

681399 is a wasteful number, since it uses less digits than its factorization.

681399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25246 (or 25240 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 681399 is about 825.4689576235. The cubic root of 681399 is about 87.9968576702.

The spelling of 681399 in words is "six hundred eighty-one thousand, three hundred ninety-nine".