66381201 has 20 divisors (see below), whose sum is σ = 99536052. Its totient is φ = 44087328.

The previous prime is 66381191. The next prime is 66381221. The reversal of 66381201 is 10218366.

66381201 is a `hidden beast` number, since 6 + 638 + 1 + 20 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 57017601 + 9363600 = 7551^2 + 3060^2 .

It is not a de Polignac number, because 66381201 - 2¹⁸ = 66119057 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (66381221) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 22335 + ... + 25131.

Almost surely, 2^66381201 is an apocalyptic number.

It is an amenable number.

66381201 is a deficient number, since it is larger than the sum of its proper divisors (33154851).

66381201 is a wasteful number, since it uses less digits than its factorization.

66381201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3102 (or 3093 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 66381201 is about 8147.4659250592. The cubic root of 66381201 is about 404.9005517140.

Adding to 66381201 its reverse (10218366), we get a palindrome (76599567).

The spelling of 66381201 in words is "sixty-six million, three hundred eighty-one thousand, two hundred one".