66752557 has 4 divisors (see below), whose sum is σ = 70679196. Its totient is φ = 62825920.

The previous prime is 66752537. The next prime is 66752561. The reversal of 66752557 is 75525766.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75525766 = 2 ⋅37762883.

It can be written as a sum of positive squares in 2 ways, for example, as 36072036 + 30680521 = 6006^2 + 5539^2 .

It is a cyclic number.

It is not a de Polignac number, because 66752557 - 2⁷ = 66752429 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 (66752527) 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, 1963294 + ... + 1963327.

It is an arithmetic number, because the mean of its divisors is an integer number (17669799).

Almost surely, 2^66752557 is an apocalyptic number.

It is an amenable number.

66752557 is a deficient number, since it is larger than the sum of its proper divisors (3926639).

66752557 is a wasteful number, since it uses less digits than its factorization.

66752557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3926638.

The product of its digits is 441000, while the sum is 43.

The square root of 66752557 is about 8170.2238035442. The cubic root of 66752557 is about 405.6541924285.

The spelling of 66752557 in words is "sixty-six million, seven hundred fifty-two thousand, five hundred fifty-seven".