66601440 has 168 divisors, whose sum is σ = 236324088. Its totient is φ = 17729280.

The previous prime is 66601421. The next prime is 66601463. The reversal of 66601440 is 4410666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 116355 + ... + 116925.

It is an arithmetic number, because the mean of its divisors is an integer number (1406691).

Almost surely, 2^66601440 is an apocalyptic number.

66601440 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 66601440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118162044).

66601440 is an abundant number, since it is smaller than the sum of its proper divisors (169722648).

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

66601440 is an equidigital number, since it uses as much as digits as its factorization.

66601440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 604 (or 581 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 66601440 is about 8160.9705305190. The cubic root of 66601440 is about 405.3478492993.

It can be divided in two parts, 6660 and 1440, that added together give a square (8100 = 90²).

The spelling of 66601440 in words is "sixty-six million, six hundred one thousand, four hundred forty".