661740569 has 8 divisors (see below), whose sum is σ = 796079040. Its totient is φ = 537353136.

The previous prime is 661740559. The next prime is 661740617. The reversal of 661740569 is 965047166.

It is a happy number.

661740569 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 661740569 - 2²⁸ = 393305113 is a prime.

It is a super-2 number, since 2×661740569² = 875801161320887522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661740529) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2487614 + ... + 2487879.

It is an arithmetic number, because the mean of its divisors is an integer number (99509880).

Almost surely, 2^661740569 is an apocalyptic number.

It is an amenable number.

661740569 is a deficient number, since it is larger than the sum of its proper divisors (134338471).

661740569 is a wasteful number, since it uses less digits than its factorization.

661740569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4975519.

The product of its (nonzero) digits is 272160, while the sum is 44.

The square root of 661740569 is about 25724.3186304322. The cubic root of 661740569 is about 871.4234718569.

The spelling of 661740569 in words is "six hundred sixty-one million, seven hundred forty thousand, five hundred sixty-nine".