66637440 has 192 divisors, whose sum is σ = 240589440. Its totient is φ = 16963584.

The previous prime is 66637429. The next prime is 66637451. The reversal of 66637440 is 4473666.

66637440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (66637429) and next prime (66637451).

It is a tau number, because it is divible by the number of its divisors (192).

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

It is a junction number, because it is equal to n+sod(n) for n = 66637395 and 66637404.

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 23 ways as a sum of consecutive naturals, for example, 132229 + ... + 132731.

It is an arithmetic number, because the mean of its divisors is an integer number (1253070).

Almost surely, 2^66637440 is an apocalyptic number.

66637440 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 66637440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120294720).

66637440 is an abundant number, since it is smaller than the sum of its proper divisors (173952000).

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

66637440 is a wasteful number, since it uses less digits than its factorization.

66637440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 551 (or 536 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 36.

The square root of 66637440 is about 8163.1758525711. The cubic root of 66637440 is about 405.4208702137.

The spelling of 66637440 in words is "sixty-six million, six hundred thirty-seven thousand, four hundred forty".