661600605 has 16 divisors (see below), whose sum is σ = 1092708864. Its totient is φ = 341471040.

The previous prime is 661600591. The next prime is 661600607. The reversal of 661600605 is 506006166.

It is not a de Polignac number, because 661600605 - 2¹⁰ = 661599581 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661600607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 710934 + ... + 711863.

It is an arithmetic number, because the mean of its divisors is an integer number (68294304).

Almost surely, 2^661600605 is an apocalyptic number.

It is an amenable number.

661600605 is a deficient number, since it is larger than the sum of its proper divisors (431108259).

661600605 is a wasteful number, since it uses less digits than its factorization.

661600605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1422836.

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 661600605 is about 25721.5980257837. The cubic root of 661600605 is about 871.3620295935.

The spelling of 661600605 in words is "six hundred sixty-one million, six hundred thousand, six hundred five".