661165063 has 4 divisors (see below), whose sum is σ = 712023928. Its totient is φ = 610306200.

The previous prime is 661165019. The next prime is 661165073. The reversal of 661165063 is 360561166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661165063 - 2²¹ = 659067911 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661165073) 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 3 ways as a sum of consecutive naturals, for example, 25429413 + ... + 25429438.

It is an arithmetic number, because the mean of its divisors is an integer number (178005982).

Almost surely, 2^661165063 is an apocalyptic number.

661165063 is a deficient number, since it is larger than the sum of its proper divisors (50858865).

661165063 is a wasteful number, since it uses less digits than its factorization.

661165063 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50858864.

The product of its (nonzero) digits is 19440, while the sum is 34.

The square root of 661165063 is about 25713.1301672900. The cubic root of 661165063 is about 871.1707772131.

The spelling of 661165063 in words is "six hundred sixty-one million, one hundred sixty-five thousand, sixty-three".