665720515020 has 48 divisors (see below), whose sum is σ = 2033473575168. Its totient is φ = 161386791360.

The previous prime is 665720515007. The next prime is 665720515039. The reversal of 665720515020 is 20515027566.

It is a self number, because there is not a number n which added to its sum of digits gives 665720515020.

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, 504333064 + ... + 504334383.

It is an arithmetic number, because the mean of its divisors is an integer number (42364032816).

Almost surely, 2^665720515020 is an apocalyptic number.

665720515020 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

665720515020 is an abundant number, since it is smaller than the sum of its proper divisors (1367753060148).

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

665720515020 is a wasteful number, since it uses less digits than its factorization.

665720515020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1008667470 (or 1008667468 counting only the distinct ones).

The product of its (nonzero) digits is 126000, while the sum is 39.

The spelling of 665720515020 in words is "six hundred sixty-five billion, seven hundred twenty million, five hundred fifteen thousand, twenty".