66781740 has 24 divisors (see below), whose sum is σ = 186989040. Its totient is φ = 17808448.

The previous prime is 66781739. The next prime is 66781747. The reversal of 66781740 is 4718766.

66781740 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (66781747) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 556455 + ... + 556574.

It is an arithmetic number, because the mean of its divisors is an integer number (7791210).

Almost surely, 2^66781740 is an apocalyptic number.

66781740 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66781740 is an abundant number, since it is smaller than the sum of its proper divisors (120207300).

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

66781740 is a wasteful number, since it uses less digits than its factorization.

66781740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1113041 (or 1113039 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 39.

The square root of 66781740 is about 8172.0095447815. The cubic root of 66781740 is about 405.7132986864.

The spelling of 66781740 in words is "sixty-six million, seven hundred eighty-one thousand, seven hundred forty".