66538433 has 4 divisors (see below), whose sum is σ = 71656788. Its totient is φ = 61420080.

The previous prime is 66538421. The next prime is 66538481. The reversal of 66538433 is 33483566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 33483566 = 2 ⋅16741783.

It can be written as a sum of positive squares in 2 ways, for example, as 20948929 + 45589504 = 4577^2 + 6752^2 .

It is a cyclic number.

It is not a de Polignac number, because 66538433 - 2⁸ = 66538177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66538403) 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, 2559158 + ... + 2559183.

It is an arithmetic number, because the mean of its divisors is an integer number (17914197).

Almost surely, 2^66538433 is an apocalyptic number.

It is an amenable number.

66538433 is a deficient number, since it is larger than the sum of its proper divisors (5118355).

66538433 is a wasteful number, since it uses less digits than its factorization.

66538433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5118354.

The product of its digits is 155520, while the sum is 38.

The square root of 66538433 is about 8157.1093531961. The cubic root of 66538433 is about 405.2199851472.

The spelling of 66538433 in words is "sixty-six million, five hundred thirty-eight thousand, four hundred thirty-three".