660313561 has 4 divisors (see below), whose sum is σ = 669613824. Its totient is φ = 651013300.

The previous prime is 660313553. The next prime is 660313571. The reversal of 660313561 is 165313066.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 660313561 - 2³ = 660313553 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660313501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4650025 + ... + 4650166.

It is an arithmetic number, because the mean of its divisors is an integer number (167403456).

Almost surely, 2^660313561 is an apocalyptic number.

It is an amenable number.

660313561 is a deficient number, since it is larger than the sum of its proper divisors (9300263).

660313561 is an equidigital number, since it uses as much as digits as its factorization.

660313561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9300262.

The product of its (nonzero) digits is 9720, while the sum is 31.

The square root of 660313561 is about 25696.5671053548. The cubic root of 660313561 is about 870.7966284161.

It can be divided in two parts, 6603 and 13561, that added together give a square (20164 = 142²).

The spelling of 660313561 in words is "six hundred sixty million, three hundred thirteen thousand, five hundred sixty-one".