66031440 has 40 divisors (see below), whose sum is σ = 204698208. Its totient is φ = 17608320.

The previous prime is 66031429. The next prime is 66031447. The reversal of 66031440 is 4413066.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 66031440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66031447) 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, 137326 + ... + 137805.

Almost surely, 2^66031440 is an apocalyptic number.

66031440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66031440 is an abundant number, since it is smaller than the sum of its proper divisors (138666768).

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

66031440 is a wasteful number, since it uses less digits than its factorization.

66031440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275147 (or 275141 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 24.

The square root of 66031440 is about 8125.9731724883. The cubic root of 66031440 is about 404.1881618686.

The spelling of 66031440 in words is "sixty-six million, thirty-one thousand, four hundred forty".