66403557 has 20 divisors (see below), whose sum is σ = 108214656. Its totient is φ = 40244040.

The previous prime is 66403549. The next prime is 66403583. The reversal of 66403557 is 75530466.

66403557 is a `hidden beast` number, since 6 + 640 + 3 + 5 + 5 + 7 = 666.

It is not a de Polignac number, because 66403557 - 2³ = 66403549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66403657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 36373 + ... + 38154.

Almost surely, 2^66403557 is an apocalyptic number.

It is an amenable number.

66403557 is a deficient number, since it is larger than the sum of its proper divisors (41811099).

66403557 is a wasteful number, since it uses less digits than its factorization.

66403557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74550 (or 74541 counting only the distinct ones).

The product of its (nonzero) digits is 75600, while the sum is 36.

The square root of 66403557 is about 8148.8377698909. The cubic root of 66403557 is about 404.9460010310.

The spelling of 66403557 in words is "sixty-six million, four hundred three thousand, five hundred fifty-seven".