566661505261 has 4 divisors (see below), whose sum is σ = 569347105024. Its totient is φ = 563975905500.

The previous prime is 566661505219. The next prime is 566661505379. The reversal of 566661505261 is 162505166665.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 162505166665 = 5 ⋅32501033333.

It is a cyclic number.

It is not a de Polignac number, because 566661505261 - 2²¹ = 566659408109 is a prime.

It is a super-2 number, since 2×566661505261² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (566661505211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1342799565 + ... + 1342799986.

It is an arithmetic number, because the mean of its divisors is an integer number (142336776256).

Almost surely, 2^566661505261 is an apocalyptic number.

It is an amenable number.

566661505261 is a deficient number, since it is larger than the sum of its proper divisors (2685599763).

566661505261 is a wasteful number, since it uses less digits than its factorization.

566661505261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2685599762.

The product of its (nonzero) digits is 1944000, while the sum is 49.

The spelling of 566661505261 in words is "five hundred sixty-six billion, six hundred sixty-one million, five hundred five thousand, two hundred sixty-one".