66540009449 has 4 divisors (see below), whose sum is σ = 66645461760. Its totient is φ = 66434557140.

The previous prime is 66540009409. The next prime is 66540009461. The reversal of 66540009449 is 94490004566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 94490004566 = 2 ⋅47245002283.

It is a cyclic number.

It is not a de Polignac number, because 66540009449 - 2²⁴ = 66523232233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66540009409) 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, 52725209 + ... + 52726470.

It is an arithmetic number, because the mean of its divisors is an integer number (16661365440).

Almost surely, 2^66540009449 is an apocalyptic number.

It is an amenable number.

66540009449 is a deficient number, since it is larger than the sum of its proper divisors (105452311).

66540009449 is a wasteful number, since it uses less digits than its factorization.

66540009449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105452310.

The product of its (nonzero) digits is 933120, while the sum is 47.

The spelling of 66540009449 in words is "sixty-six billion, five hundred forty million, nine thousand, four hundred forty-nine".