66844560 has 80 divisors (see below), whose sum is σ = 210361536. Its totient is φ = 17554944.

The previous prime is 66844559. The next prime is 66844571. The reversal of 66844560 is 6544866.

66844560 = T₁₃₆ + T₁₃₇ + ... + T₇₃₈.

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14002 + ... + 18158.

Almost surely, 2^66844560 is an apocalyptic number.

66844560 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 66844560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105180768).

66844560 is an abundant number, since it is smaller than the sum of its proper divisors (143516976).

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

66844560 is a wasteful number, since it uses less digits than its factorization.

66844560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4240 (or 4234 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 39.

The square root of 66844560 is about 8175.8522491542. The cubic root of 66844560 is about 405.8404737793.

The spelling of 66844560 in words is "sixty-six million, eight hundred forty-four thousand, five hundred sixty".