66156540 has 96 divisors (see below), whose sum is σ = 193596480. Its totient is φ = 16859136.

The previous prime is 66156539. The next prime is 66156547. The reversal of 66156540 is 4565166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66156547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 335722 + ... + 335918.

It is an arithmetic number, because the mean of its divisors is an integer number (2016630).

Almost surely, 2^66156540 is an apocalyptic number.

66156540 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 66156540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96798240).

66156540 is an abundant number, since it is smaller than the sum of its proper divisors (127439940).

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

66156540 is a wasteful number, since it uses less digits than its factorization.

66156540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431 (or 429 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 33.

The square root of 66156540 is about 8133.6670696556. The cubic root of 66156540 is about 404.4432526789.

The spelling of 66156540 in words is "sixty-six million, one hundred fifty-six thousand, five hundred forty".