66655021619 has 16 divisors (see below), whose sum is σ = 67532876448. Its totient is φ = 65784586752.

The previous prime is 66655021561. The next prime is 66655021621. The reversal of 66655021619 is 91612055666.

It is a cyclic number.

It is not a de Polignac number, because 66655021619 - 2²⁴ = 66638244403 is a prime.

It is a super-2 number, since 2×66655021619² (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 (66655021649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14310539 + ... + 14315195.

It is an arithmetic number, because the mean of its divisors is an integer number (4220804778).

Almost surely, 2^66655021619 is an apocalyptic number.

66655021619 is a deficient number, since it is larger than the sum of its proper divisors (877854829).

66655021619 is a wasteful number, since it uses less digits than its factorization.

66655021619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5414.

The product of its (nonzero) digits is 583200, while the sum is 47.

The spelling of 66655021619 in words is "sixty-six billion, six hundred fifty-five million, twenty-one thousand, six hundred nineteen".