661727166 has 16 divisors (see below), whose sum is σ = 1359223824. Its totient is φ = 214614144.

The previous prime is 661727161. The next prime is 661727173.

661727166 is nontrivially palindromic in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661727161) 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, 1490155 + ... + 1490598.

It is an arithmetic number, because the mean of its divisors is an integer number (84951489).

Almost surely, 2^661727166 is an apocalyptic number.

661727166 is an abundant number, since it is smaller than the sum of its proper divisors (697496658).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661727166 is a wasteful number, since it uses less digits than its factorization.

661727166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2980795.

The product of its digits is 127008, while the sum is 42.

The square root of 661727166 is about 25724.0581168680. The cubic root of 661727166 is about 871.4175885001.

The spelling of 661727166 in words is "six hundred sixty-one million, seven hundred twenty-seven thousand, one hundred sixty-six".