66498640 has 80 divisors (see below), whose sum is σ = 170489088. Its totient is φ = 23966208.

The previous prime is 66498637. The next prime is 66498659. The reversal of 66498640 is 4689466.

66498640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43977 + ... + 45463.

Almost surely, 2^66498640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66498640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85244544).

66498640 is an abundant number, since it is smaller than the sum of its proper divisors (103990448).

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

66498640 is a wasteful number, since it uses less digits than its factorization.

66498640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556 (or 1550 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 43.

The square root of 66498640 is about 8154.6698277735. The cubic root of 66498640 is about 405.1391890634.

The spelling of 66498640 in words is "sixty-six million, four hundred ninety-eight thousand, six hundred forty".