661710605 has 4 divisors (see below), whose sum is σ = 794052732. Its totient is φ = 529368480.

The previous prime is 661710571. The next prime is 661710629. The reversal of 661710605 is 506017166.

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

It can be written as a sum of positive squares in 2 ways, for example, as 112933129 + 548777476 = 10627^2 + 23426^2 .

It is not a de Polignac number, because 661710605 - 2⁶ = 661710541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66171056 + ... + 66171065.

It is an arithmetic number, because the mean of its divisors is an integer number (198513183).

Almost surely, 2^661710605 is an apocalyptic number.

It is an amenable number.

661710605 is a deficient number, since it is larger than the sum of its proper divisors (132342127).

661710605 is a wasteful number, since it uses less digits than its factorization.

661710605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132342126.

The product of its (nonzero) digits is 7560, while the sum is 32.

The square root of 661710605 is about 25723.7362177426. The cubic root of 661710605 is about 871.4103188035.

The spelling of 661710605 in words is "six hundred sixty-one million, seven hundred ten thousand, six hundred five".