665506859601 has 24 divisors (see below), whose sum is σ = 901058891040. Its totient is φ = 436915957632.

The previous prime is 665506859503. The next prime is 665506859617. The reversal of 665506859601 is 106958605566.

It is a happy number.

665506859601 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 665506859601 - 2¹⁴ = 665506843217 is a prime.

It is not an unprimeable number, because it can be changed into a prime (665506859201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 64865410 + ... + 64875668.

It is an arithmetic number, because the mean of its divisors is an integer number (37544120460).

Almost surely, 2^665506859601 is an apocalyptic number.

It is an amenable number.

665506859601 is a deficient number, since it is larger than the sum of its proper divisors (235552031439).

665506859601 is a wasteful number, since it uses less digits than its factorization.

665506859601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15213 (or 15146 counting only the distinct ones).

The product of its (nonzero) digits is 11664000, while the sum is 57.

The spelling of 665506859601 in words is "six hundred sixty-five billion, five hundred six million, eight hundred fifty-nine thousand, six hundred one".