681135905 has 16 divisors (see below), whose sum is σ = 846450000. Its totient is φ = 525557760.

The previous prime is 681135901. The next prime is 681135919. The reversal of 681135905 is 509531186.

It can be written as a sum of positive squares in 8 ways, for example, as 11723776 + 669412129 = 3424^2 + 25873^2 .

It is not a de Polignac number, because 681135905 - 2² = 681135901 is a prime.

It is a super-2 number, since 2×681135905² = 927892242160338050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (681135901) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 179225 + ... + 182985.

It is an arithmetic number, because the mean of its divisors is an integer number (52903125).

Almost surely, 2^681135905 is an apocalyptic number.

It is an amenable number.

681135905 is a deficient number, since it is larger than the sum of its proper divisors (165314095).

681135905 is a wasteful number, since it uses less digits than its factorization.

681135905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5044.

The product of its (nonzero) digits is 32400, while the sum is 38.

The square root of 681135905 is about 26098.5805169553. The cubic root of 681135905 is about 879.8553072193.

The spelling of 681135905 in words is "six hundred eighty-one million, one hundred thirty-five thousand, nine hundred five".