681808045 has 8 divisors (see below), whose sum is σ = 819780120. Its totient is φ = 544372800.

The previous prime is 681808031. The next prime is 681808063. The reversal of 681808045 is 540808186.

It can be written as a sum of positive squares in 4 ways, for example, as 236513641 + 445294404 = 15379^2 + 21102^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 681808045 - 2²¹ = 679710893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 681807989 and 681808007.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 131406 + ... + 136495.

It is an arithmetic number, because the mean of its divisors is an integer number (102472515).

Almost surely, 2^681808045 is an apocalyptic number.

It is an amenable number.

681808045 is a deficient number, since it is larger than the sum of its proper divisors (137972075).

681808045 is a wasteful number, since it uses less digits than its factorization.

681808045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268415.

The product of its (nonzero) digits is 61440, while the sum is 40.

The square root of 681808045 is about 26111.4542873429. The cubic root of 681808045 is about 880.1446236995.

The spelling of 681808045 in words is "six hundred eighty-one million, eight hundred eight thousand, forty-five".