66671181521 has 8 divisors (see below), whose sum is σ = 76199911104. Its totient is φ = 57143520720.

The previous prime is 66671181517. The next prime is 66671181541. The reversal of 66671181521 is 12518117666.

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 66671181521 - 2² = 66671181517 is a prime.

It is a super-2 number, since 2×66671181521² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66671181541) 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, 128735 + ... + 387188.

It is an arithmetic number, because the mean of its divisors is an integer number (9524988888).

Almost surely, 2^66671181521 is an apocalyptic number.

It is an amenable number.

66671181521 is a deficient number, since it is larger than the sum of its proper divisors (9528729583).

66671181521 is a wasteful number, since it uses less digits than its factorization.

66671181521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534391.

The product of its digits is 120960, while the sum is 44.

The spelling of 66671181521 in words is "sixty-six billion, six hundred seventy-one million, one hundred eighty-one thousand, five hundred twenty-one".