66581542 has 4 divisors (see below), whose sum is σ = 99872316. Its totient is φ = 33290770.

The previous prime is 66581513. The next prime is 66581549. The reversal of 66581542 is 24518566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24518566 = 2 ⋅12259283.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66581549) 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 as a sum of consecutive naturals, namely, 16645384 + ... + 16645387.

It is an arithmetic number, because the mean of its divisors is an integer number (24968079).

Almost surely, 2^66581542 is an apocalyptic number.

66581542 is a deficient number, since it is larger than the sum of its proper divisors (33290774).

66581542 is a wasteful number, since it uses less digits than its factorization.

66581542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33290773.

The product of its digits is 57600, while the sum is 37.

The square root of 66581542 is about 8159.7513442506. The cubic root of 66581542 is about 405.3074777254.

The spelling of 66581542 in words is "sixty-six million, five hundred eighty-one thousand, five hundred forty-two".