681387 has 16 divisors (see below), whose sum is σ = 1055232. Its totient is φ = 383040.

The previous prime is 681371. The next prime is 681403. The reversal of 681387 is 783186.

It is an interprime number because it is at equal distance from previous prime (681371) and next prime (681403).

It is not a de Polignac number, because 681387 - 2⁴ = 681371 is a prime.

It is not an unprimeable number, because it can be changed into a prime (681337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1263 + ... + 1719.

It is an arithmetic number, because the mean of its divisors is an integer number (65952).

2⁶⁸¹³⁸⁷ is an apocalyptic number.

681387 is a deficient number, since it is larger than the sum of its proper divisors (373845).

681387 is a wasteful number, since it uses less digits than its factorization.

681387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 538.

The product of its digits is 8064, while the sum is 33.

The square root of 681387 is about 825.4616889959. The cubic root of 681387 is about 87.9963411013.

The spelling of 681387 in words is "six hundred eighty-one thousand, three hundred eighty-seven".