661565007 has 12 divisors (see below), whose sum is σ = 969053904. Its totient is φ = 434831040.

The previous prime is 661564999. The next prime is 661565011. The reversal of 661565007 is 700565166.

It is a happy number.

It is not a de Polignac number, because 661565007 - 2³ = 661564999 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661560007) 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 11 ways as a sum of consecutive naturals, for example, 517018 + ... + 518295.

It is an arithmetic number, because the mean of its divisors is an integer number (80754492).

Almost surely, 2^661565007 is an apocalyptic number.

661565007 is a deficient number, since it is larger than the sum of its proper divisors (307488897).

661565007 is a wasteful number, since it uses less digits than its factorization.

661565007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1035390 (or 1035387 counting only the distinct ones).

The product of its (nonzero) digits is 37800, while the sum is 36.

The square root of 661565007 is about 25720.9060299205. The cubic root of 661565007 is about 871.3464011808.

The spelling of 661565007 in words is "six hundred sixty-one million, five hundred sixty-five thousand, seven".