666780164406 has 48 divisors (see below), whose sum is σ = 1460438525520. Its totient is φ = 219841617600.

The previous prime is 666780164383. The next prime is 666780164419. The reversal of 666780164406 is 604461087666.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1660605 + ... + 2022663.

It is an arithmetic number, because the mean of its divisors is an integer number (30425802615).

Almost surely, 2^666780164406 is an apocalyptic number.

666780164406 is an abundant number, since it is smaller than the sum of its proper divisors (793658361114).

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

666780164406 is a wasteful number, since it uses less digits than its factorization.

666780164406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363181 (or 363178 counting only the distinct ones).

The product of its (nonzero) digits is 6967296, while the sum is 54.

The spelling of 666780164406 in words is "six hundred sixty-six billion, seven hundred eighty million, one hundred sixty-four thousand, four hundred six".