66399516 has 36 divisors (see below), whose sum is σ = 169080912. Its totient is φ = 21969984.

The previous prime is 66399481. The next prime is 66399523. The reversal of 66399516 is 61599366.

66399516 is a `hidden beast` number, since 6 + 639 + 9 + 5 + 1 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1800 + ... + 11663.

It is an arithmetic number, because the mean of its divisors is an integer number (4696692).

Almost surely, 2^66399516 is an apocalyptic number.

It is an amenable number.

66399516 is an abundant number, since it is smaller than the sum of its proper divisors (102681396).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66399516 is a wasteful number, since it uses less digits than its factorization.

66399516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13610 (or 13605 counting only the distinct ones).

The product of its digits is 262440, while the sum is 45.

The square root of 66399516 is about 8148.5898166493. The cubic root of 66399516 is about 404.9377865113.

The spelling of 66399516 in words is "sixty-six million, three hundred ninety-nine thousand, five hundred sixteen".