66640048409 has 4 divisors (see below), whose sum is σ = 72698234640. Its totient is φ = 60581862180.

The previous prime is 66640048379. The next prime is 66640048417. The reversal of 66640048409 is 90484004666.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 66640048409 - 2²⁴ = 66623271193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66640048469) 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, 3029093099 + ... + 3029093120.

It is an arithmetic number, because the mean of its divisors is an integer number (18174558660).

Almost surely, 2^66640048409 is an apocalyptic number.

It is an amenable number.

66640048409 is a deficient number, since it is larger than the sum of its proper divisors (6058186231).

66640048409 is a wasteful number, since it uses less digits than its factorization.

66640048409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6058186230.

The product of its (nonzero) digits is 995328, while the sum is 47.

The spelling of 66640048409 in words is "sixty-six billion, six hundred forty million, forty-eight thousand, four hundred nine".