6406521165647 has 2 divisors, whose sum is σ = 6406521165648. Its totient is φ = 6406521165646.

The previous prime is 6406521165599. The next prime is 6406521165719. The reversal of 6406521165647 is 7465611256046.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6406521165647 - 2¹⁰ = 6406521164623 is a prime.

It is a super-2 number, since 2×6406521165647² (a number of 26 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6406521165547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3203260582823 + 3203260582824.

It is an arithmetic number, because the mean of its divisors is an integer number (3203260582824).

Almost surely, 2^{6406521165647} is an apocalyptic number.

6406521165647 is a deficient number, since it is larger than the sum of its proper divisors (1).

6406521165647 is an equidigital number, since it uses as much as digits as its factorization.

6406521165647 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7257600, while the sum is 53.

The spelling of 6406521165647 in words is "six trillion, four hundred six billion, five hundred twenty-one million, one hundred sixty-five thousand, six hundred forty-seven".