66864399 has 16 divisors (see below), whose sum is σ = 104375040. Its totient is φ = 37275840.

The previous prime is 66864397. The next prime is 66864419. The reversal of 66864399 is 99346866.

It is not a de Polignac number, because 66864399 - 2¹ = 66864397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66864397) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37969 + ... + 39690.

It is an arithmetic number, because the mean of its divisors is an integer number (6523440).

Almost surely, 2^66864399 is an apocalyptic number.

66864399 is a deficient number, since it is larger than the sum of its proper divisors (37510641).

66864399 is a wasteful number, since it uses less digits than its factorization.

66864399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77710.

The product of its digits is 1679616, while the sum is 51.

The square root of 66864399 is about 8177.0654271566. The cubic root of 66864399 is about 405.8806200168.

The spelling of 66864399 in words is "sixty-six million, eight hundred sixty-four thousand, three hundred ninety-nine".