661611597 has 16 divisors (see below), whose sum is σ = 960600000. Its totient is φ = 403449984.

The previous prime is 661611581. The next prime is 661611619. The reversal of 661611597 is 795116166.

It is not a de Polignac number, because 661611597 - 2⁴ = 661611581 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661610597) 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 15 ways as a sum of consecutive naturals, for example, 198472 + ... + 201777.

It is an arithmetic number, because the mean of its divisors is an integer number (60037500).

Almost surely, 2^661611597 is an apocalyptic number.

It is an amenable number.

661611597 is a deficient number, since it is larger than the sum of its proper divisors (298988403).

661611597 is a wasteful number, since it uses less digits than its factorization.

661611597 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400300.

The product of its digits is 68040, while the sum is 42.

The square root of 661611597 is about 25721.8116974680. The cubic root of 661611597 is about 871.3668552433.

The spelling of 661611597 in words is "six hundred sixty-one million, six hundred eleven thousand, five hundred ninety-seven".