661242165 has 8 divisors (see below), whose sum is σ = 1057987488. Its totient is φ = 352662480.

The previous prime is 661242163. The next prime is 661242167. The reversal of 661242165 is 561242166.

661242165 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (661242163) and next prime (661242167).

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

It is not a de Polignac number, because 661242165 - 2¹ = 661242163 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661242163) 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, 22041391 + ... + 22041420.

It is an arithmetic number, because the mean of its divisors is an integer number (132248436).

Almost surely, 2^661242165 is an apocalyptic number.

It is an amenable number.

661242165 is a deficient number, since it is larger than the sum of its proper divisors (396745323).

661242165 is a wasteful number, since it uses less digits than its factorization.

661242165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44082819.

The product of its digits is 17280, while the sum is 33.

The square root of 661242165 is about 25714.6293965128. The cubic root of 661242165 is about 871.2046398607.

Subtracting from 661242165 its reverse (561242166), we obtain a palindrome (99999999).

The spelling of 661242165 in words is "six hundred sixty-one million, two hundred forty-two thousand, one hundred sixty-five".