66937840 has 80 divisors (see below), whose sum is σ = 167051808. Its totient is φ = 24854528.

The previous prime is 66937837. The next prime is 66937841. The reversal of 66937840 is 4873966.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66937841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 112584 + ... + 113176.

Almost surely, 2^66937840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66937840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83525904).

66937840 is an abundant number, since it is smaller than the sum of its proper divisors (100113968).

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

66937840 is a wasteful number, since it uses less digits than its factorization.

66937840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 706 (or 700 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 43.

The square root of 66937840 is about 8181.5548644497. The cubic root of 66937840 is about 406.0291662902.

The spelling of 66937840 in words is "sixty-six million, nine hundred thirty-seven thousand, eight hundred forty".