66378785 has 12 divisors (see below), whose sum is σ = 87554964. Its totient is φ = 48275040.

The previous prime is 66378779. The next prime is 66378791. The reversal of 66378785 is 58787366.

It is an interprime number because it is at equal distance from previous prime (66378779) and next prime (66378791).

It can be written as a sum of positive squares in 2 ways, for example, as 31225744 + 35153041 = 5588^2 + 5929^2 .

It is not a de Polignac number, because 66378785 - 2⁴ = 66378769 is a prime.

It is a super-2 number, since 2×66378785² = 8812286196152450, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 54254 + ... + 55463.

It is an arithmetic number, because the mean of its divisors is an integer number (7296247).

Almost surely, 2^66378785 is an apocalyptic number.

It is an amenable number.

66378785 is a deficient number, since it is larger than the sum of its proper divisors (21176179).

66378785 is a wasteful number, since it uses less digits than its factorization.

66378785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109744 (or 109733 counting only the distinct ones).

The product of its digits is 1693440, while the sum is 50.

The square root of 66378785 is about 8147.3176567506. The cubic root of 66378785 is about 404.8956394217.

The spelling of 66378785 in words is "sixty-six million, three hundred seventy-eight thousand, seven hundred eighty-five".