66042540 has 144 divisors (see below), whose sum is σ = 211341312. Its totient is φ = 17309376.

The previous prime is 66042533. The next prime is 66042551. The reversal of 66042540 is 4524066.

It is a happy number.

66042540 is a `hidden beast` number, since 6 + 604 + 2 + 54 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 519957 + ... + 520083.

It is an arithmetic number, because the mean of its divisors is an integer number (1467648).

Almost surely, 2^66042540 is an apocalyptic number.

66042540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66042540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105670656).

66042540 is an abundant number, since it is smaller than the sum of its proper divisors (145298772).

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

66042540 is a wasteful number, since it uses less digits than its factorization.

66042540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258 (or 244 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 66042540 is about 8126.6561389049. The cubic root of 66042540 is about 404.2108088441.

The spelling of 66042540 in words is "sixty-six million, forty-two thousand, five hundred forty".