681521265 has 12 divisors (see below), whose sum is σ = 1181303604. Its totient is φ = 363477984.

The previous prime is 681521251. The next prime is 681521297. The reversal of 681521265 is 562125186.

It can be written as a sum of positive squares in 2 ways, for example, as 228342321 + 453178944 = 15111^2 + 21288^2 .

It is not a de Polignac number, because 681521265 - 2⁶ = 681521201 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7572414 + ... + 7572503.

It is an arithmetic number, because the mean of its divisors is an integer number (98441967).

Almost surely, 2^681521265 is an apocalyptic number.

It is an amenable number.

681521265 is a deficient number, since it is larger than the sum of its proper divisors (499782339).

681521265 is a wasteful number, since it uses less digits than its factorization.

681521265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15144928 (or 15144925 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 681521265 is about 26105.9622500302. The cubic root of 681521265 is about 880.0212051536.

The spelling of 681521265 in words is "six hundred eighty-one million, five hundred twenty-one thousand, two hundred sixty-five".