6445545115021 has 2 divisors, whose sum is σ = 6445545115022. Its totient is φ = 6445545115020.

The previous prime is 6445545115019. The next prime is 6445545115069. The reversal of 6445545115021 is 1205115455446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6185915122500 + 259629992521 = 2487150^2 + 509539^2 .

It is a cyclic number.

It is not a de Polignac number, because 6445545115021 - 2¹ = 6445545115019 is a prime.

It is a super-2 number, since 2×6445545115021² (a number of 26 digits) contains 22 as substring.

Together with 6445545115019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6445545115621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3222772557510 + 3222772557511.

It is an arithmetic number, because the mean of its divisors is an integer number (3222772557511).

Almost surely, 2^{6445545115021} is an apocalyptic number.

It is an amenable number.

6445545115021 is a deficient number, since it is larger than the sum of its proper divisors (1).

6445545115021 is an equidigital number, since it uses as much as digits as its factorization.

6445545115021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480000, while the sum is 43.

It can be divided in two parts, 644554 and 5115021, that added together give a palindrome (5759575).

The spelling of 6445545115021 in words is "six trillion, four hundred forty-five billion, five hundred forty-five million, one hundred fifteen thousand, twenty-one".