66560551 has 4 divisors (see below), whose sum is σ = 69454512. Its totient is φ = 63666592.

The previous prime is 66560537. The next prime is 66560569. The reversal of 66560551 is 15506566.

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

It is a cyclic number.

It is not a de Polignac number, because 66560551 - 2¹⁷ = 66429479 is a prime.

It is a super-4 number, since 4×66560551⁴ (a number of 32 digits) contains 4444 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 (66060551) 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, 1446946 + ... + 1446991.

It is an arithmetic number, because the mean of its divisors is an integer number (17363628).

Almost surely, 2^66560551 is an apocalyptic number.

66560551 is a deficient number, since it is larger than the sum of its proper divisors (2893961).

66560551 is a wasteful number, since it uses less digits than its factorization.

66560551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2893960.

The product of its (nonzero) digits is 27000, while the sum is 34.

The square root of 66560551 is about 8158.4649904256. The cubic root of 66560551 is about 405.2648798159.

It can be divided in two parts, 665 and 60551, that added together give a palindrome (61216).

The spelling of 66560551 in words is "sixty-six million, five hundred sixty thousand, five hundred fifty-one".