661322065 has 8 divisors (see below), whose sum is σ = 802503720. Its totient is φ = 523112832.

The previous prime is 661322063. The next prime is 661322071. The reversal of 661322065 is 560223166.

It can be written as a sum of positive squares in 4 ways, for example, as 128958736 + 532363329 = 11356^2 + 23073^2 .

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 661322065 - 2¹ = 661322063 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661322063) 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, 742614 + ... + 743503.

It is an arithmetic number, because the mean of its divisors is an integer number (100312965).

Almost surely, 2^661322065 is an apocalyptic number.

It is an amenable number.

661322065 is a deficient number, since it is larger than the sum of its proper divisors (141181655).

661322065 is a wasteful number, since it uses less digits than its factorization.

661322065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1486211.

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 661322065 is about 25716.1829399310. The cubic root of 661322065 is about 871.2397285926.

The spelling of 661322065 in words is "six hundred sixty-one million, three hundred twenty-two thousand, sixty-five".