66704220 has 144 divisors (see below), whose sum is σ = 224864640. Its totient is φ = 15868800.

The previous prime is 66704201. The next prime is 66704227. The reversal of 66704220 is 2240766.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66704227) 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 47 ways as a sum of consecutive naturals, for example, 116535 + ... + 117105.

It is an arithmetic number, because the mean of its divisors is an integer number (1561560).

Almost surely, 2^66704220 is an apocalyptic number.

66704220 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 66704220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112432320).

66704220 is an abundant number, since it is smaller than the sum of its proper divisors (158160420).

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

66704220 is a wasteful number, since it uses less digits than its factorization.

66704220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656 (or 651 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 66704220 is about 8167.2651481386. The cubic root of 66704220 is about 405.5562543999.

Adding to 66704220 its reverse (2240766), we get a palindrome (68944986).

The spelling of 66704220 in words is "sixty-six million, seven hundred four thousand, two hundred twenty".