66571440 has 160 divisors (see below), whose sum is σ = 234151680. Its totient is φ = 15510528.

The previous prime is 66571433. The next prime is 66571447. The reversal of 66571440 is 4417566.

It is an interprime number because it is at equal distance from previous prime (66571433) and next prime (66571447).

It is not an unprimeable number, because it can be changed into a prime (66571447) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 58719 + ... + 59841.

It is an arithmetic number, because the mean of its divisors is an integer number (1463448).

Almost surely, 2^66571440 is an apocalyptic number.

66571440 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 66571440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117075840).

66571440 is an abundant number, since it is smaller than the sum of its proper divisors (167580240).

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

66571440 is a wasteful number, since it uses less digits than its factorization.

66571440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1171 (or 1165 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 33.

The square root of 66571440 is about 8159.1323068081. The cubic root of 66571440 is about 405.2869784343.

The spelling of 66571440 in words is "sixty-six million, five hundred seventy-one thousand, four hundred forty".