666502513261 has 16 divisors (see below), whose sum is σ = 725040336384. Its totient is φ = 609007976064.

The previous prime is 666502513231. The next prime is 666502513283. The reversal of 666502513261 is 162315205666.

666502513261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 666502513261 - 2⁹ = 666502512749 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666502513231) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3174825 + ... + 3378241.

It is an arithmetic number, because the mean of its divisors is an integer number (45315021024).

Almost surely, 2^666502513261 is an apocalyptic number.

It is an amenable number.

666502513261 is a deficient number, since it is larger than the sum of its proper divisors (58537823123).

666502513261 is a wasteful number, since it uses less digits than its factorization.

666502513261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205980.

The product of its (nonzero) digits is 388800, while the sum is 43.

The spelling of 666502513261 in words is "six hundred sixty-six billion, five hundred two million, five hundred thirteen thousand, two hundred sixty-one".