66831608221544 has 96 divisors (see below), whose sum is σ = 130252938867480. Its totient is φ = 32145913110528.

The previous prime is 66831608221513. The next prime is 66831608221571. The reversal of 66831608221544 is 44512280613866.

It can be written as a sum of positive squares in 12 ways, for example, as 4460501760100 + 62371106461444 = 2111990^2 + 7897538^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 66831608221544.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3620926364 + ... + 3620944820.

Almost surely, 2^{66831608221544} is an apocalyptic number.

It is an amenable number.

66831608221544 is a deficient number, since it is larger than the sum of its proper divisors (63421330645936).

66831608221544 is a wasteful number, since it uses less digits than its factorization.

66831608221544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20455 (or 20422 counting only the distinct ones).

The product of its (nonzero) digits is 13271040, while the sum is 56.

The spelling of 66831608221544 in words is "sixty-six trillion, eight hundred thirty-one billion, six hundred eight million, two hundred twenty-one thousand, five hundred forty-four".