66287520 has 144 divisors (see below), whose sum is σ = 243675432. Its totient is φ = 16312320.

The previous prime is 66287509. The next prime is 66287521. The reversal of 66287520 is 2578266.

66287520 is a `hidden beast` number, since 6 + 628 + 7 + 5 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 38787984 + 27499536 = 6228^2 + 5244^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (66287521) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16950 + ... + 20490.

Almost surely, 2^66287520 is an apocalyptic number.

66287520 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 66287520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121837716).

66287520 is an abundant number, since it is smaller than the sum of its proper divisors (177387912).

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

66287520 is a wasteful number, since it uses less digits than its factorization.

66287520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3575 (or 3564 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 66287520 is about 8141.7148070907. The cubic root of 66287520 is about 404.7099889959.

The spelling of 66287520 in words is "sixty-six million, two hundred eighty-seven thousand, five hundred twenty".