665808578040 has 32 divisors (see below), whose sum is σ = 1997425734480. Its totient is φ = 177548954112.

The previous prime is 665808578009. The next prime is 665808578063. The reversal of 665808578040 is 40875808566.

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 7 ways as a sum of consecutive naturals, for example, 2774202289 + ... + 2774202528.

Almost surely, 2^665808578040 is an apocalyptic number.

665808578040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

665808578040 is an abundant number, since it is smaller than the sum of its proper divisors (1331617156440).

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

665808578040 is a wasteful number, since it uses less digits than its factorization.

665808578040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5548404831 (or 5548404827 counting only the distinct ones).

The product of its (nonzero) digits is 12902400, while the sum is 57.

The spelling of 665808578040 in words is "six hundred sixty-five billion, eight hundred eight million, five hundred seventy-eight thousand, forty".