66783645 has 12 divisors (see below), whose sum is σ = 115758396. Its totient is φ = 35617920.

The previous prime is 66783643. The next prime is 66783649. The reversal of 66783645 is 54638766.

It can be written as a sum of positive squares in 2 ways, for example, as 31606884 + 35176761 = 5622^2 + 5931^2 .

It is not a de Polignac number, because 66783645 - 2¹ = 66783643 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 1484081 = 66783645 / (6 + 6 + 7 + 8 + 3 + 6 + 4 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 66783645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66783643) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 741996 + ... + 742085.

It is an arithmetic number, because the mean of its divisors is an integer number (9646533).

Almost surely, 2^66783645 is an apocalyptic number.

It is an amenable number.

66783645 is a deficient number, since it is larger than the sum of its proper divisors (48974751).

66783645 is a wasteful number, since it uses less digits than its factorization.

66783645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1484092 (or 1484089 counting only the distinct ones).

The product of its digits is 725760, while the sum is 45.

The square root of 66783645 is about 8172.1261003487. The cubic root of 66783645 is about 405.7171564101.

The spelling of 66783645 in words is "sixty-six million, seven hundred eighty-three thousand, six hundred forty-five".