66613888 has 128 divisors (see below), whose sum is σ = 161274240. Its totient is φ = 27258880.

The previous prime is 66613861. The next prime is 66613901. The reversal of 66613888 is 88831666.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (46).

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, 2896245 + ... + 2896267.

It is an arithmetic number, because the mean of its divisors is an integer number (1259955).

Almost surely, 2^66613888 is an apocalyptic number.

66613888 is a gapful number since it is divisible by the number (68) 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 66613888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80637120).

66613888 is an abundant number, since it is smaller than the sum of its proper divisors (94660352).

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

66613888 is a wasteful number, since it uses less digits than its factorization.

66613888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87 (or 53 counting only the distinct ones).

The product of its digits is 331776, while the sum is 46.

The square root of 66613888 is about 8161.7331492766. The cubic root of 66613888 is about 405.3731012844.

The spelling of 66613888 in words is "sixty-six million, six hundred thirteen thousand, eight hundred eighty-eight".