66212520 has 128 divisors (see below), whose sum is σ = 219248640. Its totient is φ = 15863040.

The previous prime is 66212513. The next prime is 66212521. The reversal of 66212520 is 2521266.

66212520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (66212521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 135717 + ... + 136203.

It is an arithmetic number, because the mean of its divisors is an integer number (1712880).

Almost surely, 2^66212520 is an apocalyptic number.

66212520 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 66212520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109624320).

66212520 is an abundant number, since it is smaller than the sum of its proper divisors (153036120).

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

66212520 is a wasteful number, since it uses less digits than its factorization.

66212520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 615 (or 611 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 66212520 is about 8137.1075942254. The cubic root of 66212520 is about 404.5572970867.

Adding to 66212520 its reverse (2521266), we get a palindrome (68733786).

The spelling of 66212520 in words is "sixty-six million, two hundred twelve thousand, five hundred twenty".