661617206 has 8 divisors (see below), whose sum is σ = 993893760. Its totient is φ = 330319288.

The previous prime is 661617199. The next prime is 661617217. The reversal of 661617206 is 602716166.

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

It is a super-3 number, since 3×661617206³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 242966 + ... + 245673.

It is an arithmetic number, because the mean of its divisors is an integer number (124236720).

Almost surely, 2^661617206 is an apocalyptic number.

661617206 is a deficient number, since it is larger than the sum of its proper divisors (332276554).

661617206 is a wasteful number, since it uses less digits than its factorization.

661617206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 489318.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 661617206 is about 25721.9207292146. The cubic root of 661617206 is about 871.3693176562.

The spelling of 661617206 in words is "six hundred sixty-one million, six hundred seventeen thousand, two hundred six".