66815203256 has 8 divisors (see below), whose sum is σ = 125278506120. Its totient is φ = 33407601624.

The previous prime is 66815203253. The next prime is 66815203303. The reversal of 66815203256 is 65230251866.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×66815203256² (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 (66815203253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4175950196 + ... + 4175950211.

It is an arithmetic number, because the mean of its divisors is an integer number (15659813265).

Almost surely, 2^66815203256 is an apocalyptic number.

It is an amenable number.

66815203256 is a deficient number, since it is larger than the sum of its proper divisors (58463302864).

66815203256 is a wasteful number, since it uses less digits than its factorization.

66815203256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8351900413 (or 8351900409 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 44.

The spelling of 66815203256 in words is "sixty-six billion, eight hundred fifteen million, two hundred three thousand, two hundred fifty-six".