66398503 has 4 divisors (see below), whose sum is σ = 66608280. Its totient is φ = 66188728.

The previous prime is 66398459. The next prime is 66398513. The reversal of 66398503 is 30589366.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 30589366 = 2 ⋅15294683.

It is a cyclic number.

It is not a de Polignac number, because 66398503 - 2¹⁷ = 66267431 is a prime.

It is a super-2 number, since 2×66398503² = 8817522401282018, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66398513) 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, 104413 + ... + 105046.

It is an arithmetic number, because the mean of its divisors is an integer number (16652070).

Almost surely, 2^66398503 is an apocalyptic number.

66398503 is a deficient number, since it is larger than the sum of its proper divisors (209777).

66398503 is a wasteful number, since it uses less digits than its factorization.

66398503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209776.

The product of its (nonzero) digits is 116640, while the sum is 40.

The square root of 66398503 is about 8148.5276584178. The cubic root of 66398503 is about 404.9357272390.

The spelling of 66398503 in words is "sixty-six million, three hundred ninety-eight thousand, five hundred three".