661606045 has 12 divisors (see below), whose sum is σ = 805297500. Its totient is φ = 521810240.

The previous prime is 661606027. The next prime is 661606067. The reversal of 661606045 is 540606166.

It can be written as a sum of positive squares in 2 ways, for example, as 378458116 + 283147929 = 19454^2 + 16827^2 .

It is not a de Polignac number, because 661606045 - 2²¹ = 659508893 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661606045.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 12081 + ... + 38329.

It is an arithmetic number, because the mean of its divisors is an integer number (67108125).

Almost surely, 2^661606045 is an apocalyptic number.

It is an amenable number.

661606045 is a deficient number, since it is larger than the sum of its proper divisors (143691455).

661606045 is an equidigital number, since it uses as much as digits as its factorization.

661606045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26396 (or 26325 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 661606045 is about 25721.7037732729. The cubic root of 661606045 is about 871.3644178403.

The spelling of 661606045 in words is "six hundred sixty-one million, six hundred six thousand, forty-five".