665940906726 has 32 divisors (see below), whose sum is σ = 1338162992640. Its totient is φ = 220934114016.

The previous prime is 665940906707. The next prime is 665940906737. The reversal of 665940906726 is 627609049566.

It is a self number, because there is not a number n which added to its sum of digits gives 665940906726.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3938905 + ... + 4104491.

It is an arithmetic number, because the mean of its divisors is an integer number (41817593520).

Almost surely, 2^665940906726 is an apocalyptic number.

665940906726 is an abundant number, since it is smaller than the sum of its proper divisors (672222085914).

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

665940906726 is a wasteful number, since it uses less digits than its factorization.

665940906726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168748.

The product of its (nonzero) digits is 29393280, while the sum is 60.

The spelling of 665940906726 in words is "six hundred sixty-five billion, nine hundred forty million, nine hundred six thousand, seven hundred twenty-six".