66051720 has 128 divisors (see below), whose sum is σ = 251654400. Its totient is φ = 15095808.

The previous prime is 66051719. The next prime is 66051721. The reversal of 66051720 is 2715066.

It is an interprime number because it is at equal distance from previous prime (66051719) and next prime (66051721).

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

It is not an unprimeable number, because it can be changed into a prime (66051721) 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 31 ways as a sum of consecutive naturals, for example, 3192 + ... + 11928.

It is an arithmetic number, because the mean of its divisors is an integer number (1966050).

Almost surely, 2^66051720 is an apocalyptic number.

66051720 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 66051720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125827200).

66051720 is an abundant number, since it is smaller than the sum of its proper divisors (185602680).

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

66051720 is a wasteful number, since it uses less digits than its factorization.

66051720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8764 (or 8754 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 66051720 is about 8127.2209272297. The cubic root of 66051720 is about 404.2295365879.

Adding to 66051720 its reverse (2715066), we get a palindrome (68766786).

The spelling of 66051720 in words is "sixty-six million, fifty-one thousand, seven hundred twenty".