66378369599 has 8 divisors (see below), whose sum is σ = 68528117760. Its totient is φ = 64229153400.

The previous prime is 66378369583. The next prime is 66378369623. The reversal of 66378369599 is 99596387366.

It is a Cunningham number, because it is equal to 257640²-1.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66378369599 - 2⁴ = 66378369583 is a prime.

It is a super-4 number, since 4×66378369599⁴ (a number of 44 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66378362599) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 128822 + ... + 386460.

It is an arithmetic number, because the mean of its divisors is an integer number (8566014720).

Almost surely, 2^66378369599 is an apocalyptic number.

66378369599 is a deficient number, since it is larger than the sum of its proper divisors (2149748161).

66378369599 is a wasteful number, since it uses less digits than its factorization.

66378369599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265981.

The product of its digits is 396809280, while the sum is 71.

The spelling of 66378369599 in words is "sixty-six billion, three hundred seventy-eight million, three hundred sixty-nine thousand, five hundred ninety-nine".