66256640 has 72 divisors (see below), whose sum is σ = 163111200. Its totient is φ = 25767936.

The previous prime is 66256637. The next prime is 66256643. The reversal of 66256640 is 4665266.

It is an interprime number because it is at equal distance from previous prime (66256637) and next prime (66256643).

It is a self number, because there is not a number n which added to its sum of digits gives 66256640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66256643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46661 + ... + 48059.

Almost surely, 2^66256640 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 66256640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81555600).

66256640 is an abundant number, since it is smaller than the sum of its proper divisors (96854560).

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

66256640 is a wasteful number, since it uses less digits than its factorization.

66256640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1457 (or 1443 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 35.

The square root of 66256640 is about 8139.8181797876. The cubic root of 66256640 is about 404.6471346023.

The spelling of 66256640 in words is "sixty-six million, two hundred fifty-six thousand, six hundred forty".