66240720 has 320 divisors, whose sum is σ = 281648640. Its totient is φ = 13934592.

The previous prime is 66240709. The next prime is 66240731. The reversal of 66240720 is 2704266.

It is an interprime number because it is at equal distance from previous prime (66240709) and next prime (66240731).

It is a super-2 number, since 2×66240720² = 8775665972236800, which contains 22 as substring.

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 63 ways as a sum of consecutive naturals, for example, 196392 + ... + 196728.

It is an arithmetic number, because the mean of its divisors is an integer number (880152).

Almost surely, 2^66240720 is an apocalyptic number.

66240720 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 66240720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140824320).

66240720 is an abundant number, since it is smaller than the sum of its proper divisors (215407920).

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

66240720 is a wasteful number, since it uses less digits than its factorization.

66240720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 379 (or 367 counting only the distinct ones).

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

The square root of 66240720 is about 8138.8402122170. The cubic root of 66240720 is about 404.6147227645.

Adding to 66240720 its reverse (2704266), we get a palindrome (68944986).

The spelling of 66240720 in words is "sixty-six million, two hundred forty thousand, seven hundred twenty".