66978383 has 8 divisors (see below), whose sum is σ = 69273600. Its totient is φ = 64691640.

The previous prime is 66978367. The next prime is 66978389. The reversal of 66978383 is 38387966.

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 66978383 - 2⁴ = 66978367 is a prime.

It is a super-3 number, since 3×66978383³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66978389) 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, 16766 + ... + 20372.

It is an arithmetic number, because the mean of its divisors is an integer number (8659200).

Almost surely, 2^66978383 is an apocalyptic number.

66978383 is a deficient number, since it is larger than the sum of its proper divisors (2295217).

66978383 is a wasteful number, since it uses less digits than its factorization.

66978383 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4237.

The product of its digits is 1306368, while the sum is 50.

The square root of 66978383 is about 8184.0321969064. The cubic root of 66978383 is about 406.1111245075. Note that the first 4 decimals are identical.

The spelling of 66978383 in words is "sixty-six million, nine hundred seventy-eight thousand, three hundred eighty-three".