66530640 has 240 divisors, whose sum is σ = 237484800. Its totient is φ = 15375360.

The previous prime is 66530627. The next prime is 66530641. The reversal of 66530640 is 4603566.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 66530598 and 66530607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66530641) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 842121 + ... + 842199.

It is an arithmetic number, because the mean of its divisors is an integer number (989520).

Almost surely, 2^66530640 is an apocalyptic number.

66530640 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 66530640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118742400).

66530640 is an abundant number, since it is smaller than the sum of its proper divisors (170954160).

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

66530640 is a wasteful number, since it uses less digits than its factorization.

66530640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146 (or 129 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 30.

The square root of 66530640 is about 8156.6316577372. The cubic root of 66530640 is about 405.2041647033.

The spelling of 66530640 in words is "sixty-six million, five hundred thirty thousand, six hundred forty".