66521654757 has 40 divisors (see below), whose sum is σ = 106494976896. Its totient is φ = 41273087328.

The previous prime is 66521654753. The next prime is 66521654809. The reversal of 66521654757 is 75745612566.

It is a happy number.

66521654757 is a `hidden beast` number, since 6 + 6 + 5 + 2 + 165 + 475 + 7 = 666.

It is not a de Polignac number, because 66521654757 - 2² = 66521654753 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66521654753) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 413593 + ... + 551454.

Almost surely, 2^66521654757 is an apocalyptic number.

It is an amenable number.

66521654757 is a deficient number, since it is larger than the sum of its proper divisors (39973322139).

66521654757 is a wasteful number, since it uses less digits than its factorization.

66521654757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 965119 (or 965110 counting only the distinct ones).

The product of its digits is 10584000, while the sum is 54.

The spelling of 66521654757 in words is "sixty-six billion, five hundred twenty-one million, six hundred fifty-four thousand, seven hundred fifty-seven".