66909816 has 24 divisors (see below), whose sum is σ = 181214280. Its totient is φ = 22303248.

The previous prime is 66909809. The next prime is 66909847. The reversal of 66909816 is 61890966.

It is a tau number, because it is divible by the number of its divisors (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 464580 + ... + 464723.

It is an arithmetic number, because the mean of its divisors is an integer number (7550595).

Almost surely, 2^66909816 is an apocalyptic number.

It is an amenable number.

66909816 is an abundant number, since it is smaller than the sum of its proper divisors (114304464).

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

66909816 is a wasteful number, since it uses less digits than its factorization.

66909816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 929315 (or 929308 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 66909816 is about 8179.8420522648. The cubic root of 66909816 is about 405.9724960539.

The spelling of 66909816 in words is "sixty-six million, nine hundred nine thousand, eight hundred sixteen".