66780407 has 4 divisors (see below), whose sum is σ = 66856920. Its totient is φ = 66703896.

The previous prime is 66780379. The next prime is 66780443. The reversal of 66780407 is 70408766.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70408766 = 2 ⋅35204383.

It is a cyclic number.

It is not a de Polignac number, because 66780407 - 2⁸ = 66780151 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66780457) 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, 36932 + ... + 38697.

It is an arithmetic number, because the mean of its divisors is an integer number (16714230).

Almost surely, 2^66780407 is an apocalyptic number.

66780407 is a deficient number, since it is larger than the sum of its proper divisors (76513).

66780407 is an equidigital number, since it uses as much as digits as its factorization.

66780407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76512.

The product of its (nonzero) digits is 56448, while the sum is 38.

The square root of 66780407 is about 8171.9279854879. The cubic root of 66780407 is about 405.7105992488.

The spelling of 66780407 in words is "sixty-six million, seven hundred eighty thousand, four hundred seven".