681009121 has 8 divisors (see below), whose sum is σ = 733702760. Its totient is φ = 628359552.

The previous prime is 681009101. The next prime is 681009143. The reversal of 681009121 is 121900186.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 71166096 + 609843025 = 8436^2 + 24695^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 681009121 - 2⁵ = 681009089 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 681009121.

It is not an unprimeable number, because it can be changed into a prime (681009101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25615 + ... + 44923.

It is an arithmetic number, because the mean of its divisors is an integer number (91712845).

Almost surely, 2^681009121 is an apocalyptic number.

It is an amenable number.

681009121 is a deficient number, since it is larger than the sum of its proper divisors (52693639).

681009121 is a wasteful number, since it uses less digits than its factorization.

681009121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22035.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 681009121 is about 26096.1514595543. The cubic root of 681009121 is about 879.8007128785.

The spelling of 681009121 in words is "six hundred eighty-one million, nine thousand, one hundred twenty-one".