66640351 has 4 divisors (see below), whose sum is σ = 66665872. Its totient is φ = 66614832.

The previous prime is 66640339. The next prime is 66640363. The reversal of 66640351 is 15304666.

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

It is an interprime number because it is at equal distance from previous prime (66640339) and next prime (66640363).

It is a cyclic number.

It is not a de Polignac number, because 66640351 - 2¹¹ = 66638303 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66640331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8331 + ... + 14236.

It is an arithmetic number, because the mean of its divisors is an integer number (16666468).

Almost surely, 2^66640351 is an apocalyptic number.

66640351 is a deficient number, since it is larger than the sum of its proper divisors (25521).

66640351 is a wasteful number, since it uses less digits than its factorization.

66640351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25520.

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 66640351 is about 8163.3541513277. The cubic root of 66640351 is about 405.4267736166.

The spelling of 66640351 in words is "sixty-six million, six hundred forty thousand, three hundred fifty-one".