681633 has 12 divisors (see below), whose sum is σ = 1003860. Its totient is φ = 445536.

The previous prime is 681631. The next prime is 681647. The reversal of 681633 is 336186.

It can be written as a sum of positive squares in 2 ways, for example, as 242064 + 439569 = 492^2 + 663^2 .

It is not a de Polignac number, because 681633 - 2¹ = 681631 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

681633 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 681597 and 681606.

It is not an unprimeable number, because it can be changed into a prime (681631) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 238 + ... + 1191.

It is an arithmetic number, because the mean of its divisors is an integer number (83655).

2⁶⁸¹⁶³³ is an apocalyptic number.

681633 is the 477-th octagonal number.

It is an amenable number.

681633 is a deficient number, since it is larger than the sum of its proper divisors (322227).

681633 is a wasteful number, since it uses less digits than its factorization.

681633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1488 (or 1485 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 681633 is about 825.6106830704. The cubic root of 681633 is about 88.0069295507.

The spelling of 681633 in words is "six hundred eighty-one thousand, six hundred thirty-three".