661595045 has 6 divisors (see below), whose sum is σ = 793983078. Its totient is φ = 529230024.

The previous prime is 661595027. The next prime is 661595047. The reversal of 661595045 is 540595166.

It can be written as a sum of positive squares in only one way, i.e., 529276036 + 132319009 = 23006^2 + 11503^2 .

It is not a de Polignac number, because 661595045 - 2⁶ = 661594981 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 661594993 and 661595011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661595047) 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 5 ways as a sum of consecutive naturals, for example, 51764 + ... + 63266.

It is an arithmetic number, because the mean of its divisors is an integer number (132330513).

Almost surely, 2^661595045 is an apocalyptic number.

It is an amenable number.

661595045 is a deficient number, since it is larger than the sum of its proper divisors (132388033).

661595045 is an frugal number, since it uses more digits than its factorization.

661595045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23011 (or 11508 counting only the distinct ones).

The product of its (nonzero) digits is 162000, while the sum is 41.

The square root of 661595045 is about 25721.4899451801. The cubic root of 661595045 is about 871.3595886514.

Multiplying 661595045 by its product of nonzero digits (162000), we get a square (107178397290000 = 10352700²).

The spelling of 661595045 in words is "six hundred sixty-one million, five hundred ninety-five thousand, forty-five".