681544 has 8 divisors (see below), whose sum is σ = 1277910. Its totient is φ = 340768.

The previous prime is 681539. The next prime is 681557. The reversal of 681544 is 445186.

It can be written as a sum of positive squares in only one way, i.e., 544644 + 136900 = 738^2 + 370^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42589 + ... + 42604.

2⁶⁸¹⁵⁴⁴ is an apocalyptic number.

It is an amenable number.

681544 is a deficient number, since it is larger than the sum of its proper divisors (596366).

681544 is a wasteful number, since it uses less digits than its factorization.

681544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85199 (or 85195 counting only the distinct ones).

The product of its digits is 3840, while the sum is 28.

The square root of 681544 is about 825.5567818146. The cubic root of 681544 is about 88.0030990644.

It can be divided in two parts, 6815 and 44, that added together give a cube (6859 = 19³).

The spelling of 681544 in words is "six hundred eighty-one thousand, five hundred forty-four".