665121234715651 has 12 divisors (see below), whose sum is σ = 773965221489840. Its totient is φ = 569917667738160.

The previous prime is 665121234715607. The next prime is 665121234715657. The reversal of 665121234715651 is 156517432121566.

It is not a de Polignac number, because 665121234715651 - 2¹³ = 665121234707459 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 665121234715592 and 665121234715601.

It is not an unprimeable number, because it can be changed into a prime (665121234715657) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2217083391 + ... + 2217383368.

It is an arithmetic number, because the mean of its divisors is an integer number (64497101790820).

Almost surely, 2^{665121234715651} is an apocalyptic number.

665121234715651 is a deficient number, since it is larger than the sum of its proper divisors (108843986774189).

665121234715651 is a wasteful number, since it uses less digits than its factorization.

665121234715651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4434469834 (or 4434469827 counting only the distinct ones).

The product of its digits is 9072000, while the sum is 55.

The spelling of 665121234715651 in words is "six hundred sixty-five trillion, one hundred twenty-one billion, two hundred thirty-four million, seven hundred fifteen thousand, six hundred fifty-one".