66404351 has 4 divisors (see below), whose sum is σ = 71512392. Its totient is φ = 61296312.

The previous prime is 66404347. The next prime is 66404353. The reversal of 66404351 is 15340466.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15340466 = 2 ⋅7670233.

It is a cyclic number.

It is not a de Polignac number, because 66404351 - 2² = 66404347 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 (66404353) 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, 2554001 + ... + 2554026.

It is an arithmetic number, because the mean of its divisors is an integer number (17878098).

Almost surely, 2^66404351 is an apocalyptic number.

66404351 is a deficient number, since it is larger than the sum of its proper divisors (5108041).

66404351 is a wasteful number, since it uses less digits than its factorization.

66404351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5108040.

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 66404351 is about 8148.8864883492. The cubic root of 66404351 is about 404.9476150301.

The spelling of 66404351 in words is "sixty-six million, four hundred four thousand, three hundred fifty-one".