6561206757669 has 4 divisors (see below), whose sum is σ = 8748275676896. Its totient is φ = 4374137838444.

The previous prime is 6561206757649. The next prime is 6561206757671. The reversal of 6561206757669 is 9667576021656.

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 not a de Polignac number, because 6561206757669 - 2²⁴ = 6561189980453 is a prime.

It is a super-2 number, since 2×6561206757669² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561206757649) 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, 1093534459609 + ... + 1093534459614.

It is an arithmetic number, because the mean of its divisors is an integer number (2187068919224).

Almost surely, 2^{6561206757669} is an apocalyptic number.

It is an amenable number.

6561206757669 is a deficient number, since it is larger than the sum of its proper divisors (2187068919227).

6561206757669 is a wasteful number, since it uses less digits than its factorization.

6561206757669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2187068919226.

The product of its (nonzero) digits is 171460800, while the sum is 66.

The spelling of 6561206757669 in words is "six trillion, five hundred sixty-one billion, two hundred six million, seven hundred fifty-seven thousand, six hundred sixty-nine".