66549953 has 4 divisors (see below), whose sum is σ = 66597828. Its totient is φ = 66502080.

The previous prime is 66549947. The next prime is 66549991. The reversal of 66549953 is 35994566.

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

It can be written as a sum of positive squares in 2 ways, for example, as 32069569 + 34480384 = 5663^2 + 5872^2 .

It is a cyclic number.

It is not a de Polignac number, because 66549953 - 2²⁰ = 65501377 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66549898 and 66549907.

It is not an unprimeable number, because it can be changed into a prime (66549943) 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, 21788 + ... + 24653.

It is an arithmetic number, because the mean of its divisors is an integer number (16649457).

Almost surely, 2^66549953 is an apocalyptic number.

It is an amenable number.

66549953 is a deficient number, since it is larger than the sum of its proper divisors (47875).

66549953 is a wasteful number, since it uses less digits than its factorization.

66549953 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47874.

The product of its digits is 874800, while the sum is 47.

The square root of 66549953 is about 8157.8154551326. The cubic root of 66549953 is about 405.2433694513.

The spelling of 66549953 in words is "sixty-six million, five hundred forty-nine thousand, nine hundred fifty-three".