66515061555 has 12 divisors (see below), whose sum is σ = 115292773440. Its totient is φ = 35474699472.

The previous prime is 66515061553. The next prime is 66515061589. The reversal of 66515061555 is 55516051566.

It is not a de Polignac number, because 66515061555 - 2¹ = 66515061553 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 1478112479 = 66515061555 / (6 + 6 + 5 + 1 + 5 + 0 + 6 + 1 + 5 + 5 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 66515061555.

It is not an unprimeable number, because it can be changed into a prime (66515061553) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 739056195 + ... + 739056284.

It is an arithmetic number, because the mean of its divisors is an integer number (9607731120).

Almost surely, 2^66515061555 is an apocalyptic number.

66515061555 is a deficient number, since it is larger than the sum of its proper divisors (48777711885).

66515061555 is a wasteful number, since it uses less digits than its factorization.

66515061555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1478112490 (or 1478112487 counting only the distinct ones).

The product of its (nonzero) digits is 675000, while the sum is 45.

The spelling of 66515061555 in words is "sixty-six billion, five hundred fifteen million, sixty-one thousand, five hundred fifty-five".