961721785 has 4 divisors (see below), whose sum is σ = 1154066148. Its totient is φ = 769377424.

The previous prime is 961721759. The next prime is 961721837. The reversal of 961721785 is 587127169.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 587127169 = 1327 ⋅442447.

It can be written as a sum of positive squares in 2 ways, for example, as 154480041 + 807241744 = 12429^2 + 28412^2 .

It is a cyclic number.

It is not a de Polignac number, because 961721785 - 2²⁹ = 424850873 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 96172174 + ... + 96172183.

It is an arithmetic number, because the mean of its divisors is an integer number (288516537).

Almost surely, 2^961721785 is an apocalyptic number.

It is an amenable number.

961721785 is a deficient number, since it is larger than the sum of its proper divisors (192344363).

961721785 is a wasteful number, since it uses less digits than its factorization.

961721785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192344362.

The product of its digits is 211680, while the sum is 46.

The square root of 961721785 is about 31011.6395084168. The cubic root of 961721785 is about 987.0742395758.

The spelling of 961721785 in words is "nine hundred sixty-one million, seven hundred twenty-one thousand, seven hundred eighty-five".