661380658166 has 8 divisors (see below), whose sum is σ = 1050428104200. Its totient is φ = 311237956768.

The previous prime is 661380658163. The next prime is 661380658187. The reversal of 661380658166 is 661856083166.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661380658163) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9726186116 + ... + 9726186183.

It is an arithmetic number, because the mean of its divisors is an integer number (131303513025).

Almost surely, 2^661380658166 is an apocalyptic number.

661380658166 is a deficient number, since it is larger than the sum of its proper divisors (389047446034).

661380658166 is a wasteful number, since it uses less digits than its factorization.

661380658166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19452372318.

The product of its (nonzero) digits is 7464960, while the sum is 56.

The spelling of 661380658166 in words is "six hundred sixty-one billion, three hundred eighty million, six hundred fifty-eight thousand, one hundred sixty-six".