661236632166 has 32 divisors (see below), whose sum is σ = 1447796020608. Its totient is φ = 199666693440.

The previous prime is 661236632137. The next prime is 661236632167.

661236632166 is nontrivially palindromic in base 10.

661236632166 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661236632167) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17682271 + ... + 17719626.

It is an arithmetic number, because the mean of its divisors is an integer number (45243625644).

Almost surely, 2^661236632166 is an apocalyptic number.

661236632166 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

661236632166 is an abundant number, since it is smaller than the sum of its proper divisors (786559388442).

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

661236632166 is a wasteful number, since it uses less digits than its factorization.

661236632166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35402196.

The product of its digits is 1679616, while the sum is 48.

The spelling of 661236632166 in words is "six hundred sixty-one billion, two hundred thirty-six million, six hundred thirty-two thousand, one hundred sixty-six".