66538480 has 20 divisors (see below), whose sum is σ = 154702152. Its totient is φ = 26615360.

The previous prime is 66538421. The next prime is 66538481. The reversal of 66538480 is 8483566.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66538481) 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 3 ways as a sum of consecutive naturals, for example, 415786 + ... + 415945.

Almost surely, 2^66538480 is an apocalyptic number.

It is an amenable number.

66538480 is an abundant number, since it is smaller than the sum of its proper divisors (88163672).

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

66538480 is a wasteful number, since it uses less digits than its factorization.

66538480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 831744 (or 831738 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 40.

The square root of 66538480 is about 8157.1122341182. The cubic root of 66538480 is about 405.2200805574.

The spelling of 66538480 in words is "sixty-six million, five hundred thirty-eight thousand, four hundred eighty".