66207406864 has 15 divisors (see below), whose sum is σ = 128278844967. Its totient is φ = 33103188816.

The previous prime is 66207406849. The next prime is 66207406871. The reversal of 66207406864 is 46860470266.

It is a happy number.

The square root of 66207406864 is 257308.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 997069 + ... + 1061395.

Almost surely, 2^66207406864 is an apocalyptic number.

66207406864 is the 257308-th square number.

It is an amenable number.

66207406864 is a deficient number, since it is larger than the sum of its proper divisors (62071438103).

66207406864 is an frugal number, since it uses more digits than its factorization.

66207406864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128662 (or 64329 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 49.

Multiplying 66207406864 by its sum of digits (49), we get a square (3244162936336 = 1801156²).

The spelling of 66207406864 in words is "sixty-six billion, two hundred seven million, four hundred six thousand, eight hundred sixty-four".