66560501561557 has 4 divisors (see below), whose sum is σ = 66592486427436. Its totient is φ = 66528516695680.

The previous prime is 66560501561527. The next prime is 66560501561621. The reversal of 66560501561557 is 75516510506566.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 41922918493681 + 24637583067876 = 6474791^2 + 4963626^2 .

It is a cyclic number.

It is not a de Polignac number, because 66560501561557 - 2⁴³ = 57764408539349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66560501561527) 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, 15992429818 + ... + 15992433979.

It is an arithmetic number, because the mean of its divisors is an integer number (16648121606859).

Almost surely, 2^{66560501561557} is an apocalyptic number.

It is an amenable number.

66560501561557 is a deficient number, since it is larger than the sum of its proper divisors (31984865879).

66560501561557 is a wasteful number, since it uses less digits than its factorization.

66560501561557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31984865878.

The product of its (nonzero) digits is 28350000, while the sum is 58.

The spelling of 66560501561557 in words is "sixty-six trillion, five hundred sixty billion, five hundred one million, five hundred sixty-one thousand, five hundred fifty-seven".