66457440 has 288 divisors, whose sum is σ = 273611520. Its totient is φ = 14349312.

The previous prime is 66457399. The next prime is 66457441. The reversal of 66457440 is 4475466.

66457440 is a `hidden beast` number, since 6 + 645 + 7 + 4 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

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 = 66457395 and 66457404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66457441) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 191347 + ... + 191693.

It is an arithmetic number, because the mean of its divisors is an integer number (950040).

Almost surely, 2^66457440 is an apocalyptic number.

66457440 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 66457440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136805760).

66457440 is an abundant number, since it is smaller than the sum of its proper divisors (207154080).

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

66457440 is a wasteful number, since it uses less digits than its factorization.

66457440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394 (or 383 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 36.

The square root of 66457440 is about 8152.1432764642. The cubic root of 66457440 is about 405.0555022243.

The spelling of 66457440 in words is "sixty-six million, four hundred fifty-seven thousand, four hundred forty".