66540384 has 144 divisors (see below), whose sum is σ = 202849920. Its totient is φ = 20643840.

The previous prime is 66540379. The next prime is 66540401. The reversal of 66540384 is 48304566.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 258784 + ... + 259040.

It is an arithmetic number, because the mean of its divisors is an integer number (1408680).

Almost surely, 2^66540384 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 66540384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101424960).

66540384 is an abundant number, since it is smaller than the sum of its proper divisors (136309536).

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

66540384 is a wasteful number, since it uses less digits than its factorization.

66540384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333 (or 322 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The square root of 66540384 is about 8157.2289412520. The cubic root of 66540384 is about 405.2239456475.

The spelling of 66540384 in words is "sixty-six million, five hundred forty thousand, three hundred eighty-four".