6505506721 has 16 divisors (see below), whose sum is σ = 7472602368. Its totient is φ = 5547902400.

The previous prime is 6505506719. The next prime is 6505506743. The reversal of 6505506721 is 1276055056.

It is a cyclic number.

It is not a de Polignac number, because 6505506721 - 2¹ = 6505506719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6505506701) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1877931 + ... + 1881391.

It is an arithmetic number, because the mean of its divisors is an integer number (467037648).

Almost surely, 2^6505506721 is an apocalyptic number.

It is an amenable number.

6505506721 is a deficient number, since it is larger than the sum of its proper divisors (967095647).

6505506721 is a wasteful number, since it uses less digits than its factorization.

6505506721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4752.

The product of its (nonzero) digits is 63000, while the sum is 37.

The square root of 6505506721 is about 80656.7214868048. The cubic root of 6505506721 is about 1866.7824526641.

The spelling of 6505506721 in words is "six billion, five hundred five million, five hundred six thousand, seven hundred twenty-one".