66716823615 has 64 divisors (see below), whose sum is σ = 118727078400. Its totient is φ = 31778348544.

The previous prime is 66716823601. The next prime is 66716823617. The reversal of 66716823615 is 51632861766.

It is a Cunningham number, because it is equal to 258296²-1.

It is not a de Polignac number, because 66716823615 - 2⁴ = 66716823599 is a prime.

It is a super-2 number, since 2×66716823615² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66716823617) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 1265656 + ... + 1317314.

It is an arithmetic number, because the mean of its divisors is an integer number (1855110600).

Almost surely, 2^66716823615 is an apocalyptic number.

66716823615 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

66716823615 is a deficient number, since it is larger than the sum of its proper divisors (52010254785).

66716823615 is a wasteful number, since it uses less digits than its factorization.

66716823615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51896.

The product of its digits is 2177280, while the sum is 51.

The spelling of 66716823615 in words is "sixty-six billion, seven hundred sixteen million, eight hundred twenty-three thousand, six hundred fifteen".