66381001 has 4 divisors (see below), whose sum is σ = 66666132. Its totient is φ = 66095872.

The previous prime is 66380969. The next prime is 66381011. The reversal of 66381001 is 10018366.

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

It can be written as a sum of positive squares in 2 ways, for example, as 34164025 + 32216976 = 5845^2 + 5676^2 .

It is a cyclic number.

It is not a de Polignac number, because 66381001 - 2⁵ = 66380969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66381011) 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, 142216 + ... + 142681.

It is an arithmetic number, because the mean of its divisors is an integer number (16666533).

Almost surely, 2^66381001 is an apocalyptic number.

It is an amenable number.

66381001 is a deficient number, since it is larger than the sum of its proper divisors (285131).

66381001 is a wasteful number, since it uses less digits than its factorization.

66381001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285130.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 66381001 is about 8147.4536512950. The cubic root of 66381001 is about 404.9001450718.

Adding to 66381001 its reverse (10018366), we get a palindrome (76399367).

The spelling of 66381001 in words is "sixty-six million, three hundred eighty-one thousand, one".