66916840 has 16 divisors (see below), whose sum is σ = 150562980. Its totient is φ = 26766720.

The previous prime is 66916819. The next prime is 66916849. The reversal of 66916840 is 4861966.

It can be written as a sum of positive squares in 2 ways, for example, as 64995844 + 1920996 = 8062^2 + 1386^2 .

It is a Harshad number since it is a multiple of its sum of digits (40), and also a Moran number because the ratio is a prime number: 1672921 = 66916840 / (6 + 6 + 9 + 1 + 6 + 8 + 4 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 66916793 and 66916802.

It is not an unprimeable number, because it can be changed into a prime (66916849) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 836421 + ... + 836500.

Almost surely, 2^66916840 is an apocalyptic number.

It is an amenable number.

66916840 is an abundant number, since it is smaller than the sum of its proper divisors (83646140).

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

66916840 is a wasteful number, since it uses less digits than its factorization.

66916840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1672932 (or 1672928 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 66916840 is about 8180.2713891411. The cubic root of 66916840 is about 405.9867014985.

It can be divided in two parts, 6691 and 6840, that added together give a palindrome (13531).

The spelling of 66916840 in words is "sixty-six million, nine hundred sixteen thousand, eight hundred forty".