66712121775 has 48 divisors (see below), whose sum is σ = 131979781920. Its totient is φ = 32842886400.

The previous prime is 66712121753. The next prime is 66712121813. The reversal of 66712121775 is 57712121766.

It is not a de Polignac number, because 66712121775 - 2⁸ = 66712121519 is a prime.

It is a super-3 number, since 3×66712121775³ (a number of 33 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 66712121775.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3792486 + ... + 3810035.

It is an arithmetic number, because the mean of its divisors is an integer number (2749578790).

Almost surely, 2^66712121775 is an apocalyptic number.

66712121775 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

66712121775 is a deficient number, since it is larger than the sum of its proper divisors (65267660145).

66712121775 is a wasteful number, since it uses less digits than its factorization.

66712121775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7602553 (or 7602542 counting only the distinct ones).

The product of its digits is 246960, while the sum is 45.

Subtracting from 66712121775 its reverse (57712121766), we obtain a palindrome (9000000009).

The spelling of 66712121775 in words is "sixty-six billion, seven hundred twelve million, one hundred twenty-one thousand, seven hundred seventy-five".