40645666 has 4 divisors (see below), whose sum is σ = 60968502. Its totient is φ = 20322832.

The previous prime is 40645663. The next prime is 40645711. The reversal of 40645666 is 66654604.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 40640625 + 5041 = 6375^2 + 71^2 .

It is not an unprimeable number, because it can be changed into a prime (40645663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10161415 + ... + 10161418.

Almost surely, 2^40645666 is an apocalyptic number.

40645666 is a deficient number, since it is larger than the sum of its proper divisors (20322836).

40645666 is a wasteful number, since it uses less digits than its factorization.

40645666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20322835.

The product of its (nonzero) digits is 103680, while the sum is 37.

The square root of 40645666 is about 6375.3953602894. The cubic root of 40645666 is about 343.8254985243.

It can be divided in two parts, 4064 and 5666, that added together give a triangular number (9730 = T₁₃₉).

The spelling of 40645666 in words is "forty million, six hundred forty-five thousand, six hundred sixty-six".