66830640 has 80 divisors (see below), whose sum is σ = 216200448. Its totient is φ = 17045248.

The previous prime is 66830639. The next prime is 66830641. The reversal of 66830640 is 4603866.

It is an interprime number because it is at equal distance from previous prime (66830639) and next prime (66830641).

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (66830641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 534 + ... + 11573.

Almost surely, 2^66830640 is an apocalyptic number.

66830640 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 66830640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108100224).

66830640 is an abundant number, since it is smaller than the sum of its proper divisors (149369808).

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

66830640 is a wasteful number, since it uses less digits than its factorization.

66830640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12146 (or 12140 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 33.

The square root of 66830640 is about 8175.0009174311. Note that the first 3 decimals coincide. The cubic root of 66830640 is about 405.8123004989.

The spelling of 66830640 in words is "sixty-six million, eight hundred thirty thousand, six hundred forty".