66881520 has 120 divisors (see below), whose sum is σ = 236480400. Its totient is φ = 16892928.

The previous prime is 66881489. The next prime is 66881531. The reversal of 66881520 is 2518866.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (120).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11236 + ... + 16124.

It is an arithmetic number, because the mean of its divisors is an integer number (1970670).

Almost surely, 2^66881520 is an apocalyptic number.

66881520 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 66881520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118240200).

66881520 is an abundant number, since it is smaller than the sum of its proper divisors (169598880).

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

66881520 is a wasteful number, since it uses less digits than its factorization.

66881520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4927 (or 4918 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 66881520 is about 8178.1122516141. The cubic root of 66881520 is about 405.9152597213.

The spelling of 66881520 in words is "sixty-six million, eight hundred eighty-one thousand, five hundred twenty".