66519521 has 8 divisors (see below), whose sum is σ = 72705024. Its totient is φ = 60586560.

The previous prime is 66519517. The next prime is 66519529. The reversal of 66519521 is 12591566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66519521 - 2² = 66519517 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66519529) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62585 + ... + 63638.

It is an arithmetic number, because the mean of its divisors is an integer number (9088128).

Almost surely, 2^66519521 is an apocalyptic number.

It is an amenable number.

66519521 is a deficient number, since it is larger than the sum of its proper divisors (6185503).

66519521 is a wasteful number, since it uses less digits than its factorization.

66519521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126271.

The product of its digits is 16200, while the sum is 35.

The square root of 66519521 is about 8155.9500366297. The cubic root of 66519521 is about 405.1815900614.

The spelling of 66519521 in words is "sixty-six million, five hundred nineteen thousand, five hundred twenty-one".