6445642819 has 12 divisors (see below), whose sum is σ = 8179629048. Its totient is φ = 5022578400.

The previous prime is 6445642789. The next prime is 6445642829. The reversal of 6445642819 is 9182465446.

It is not a de Polignac number, because 6445642819 - 2⁵ = 6445642787 is a prime.

It is a super-2 number, since 2×6445642819² = 83092622700252533522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6445642829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5978722 + ... + 5979799.

It is an arithmetic number, because the mean of its divisors is an integer number (681635754).

Almost surely, 2^6445642819 is an apocalyptic number.

6445642819 is a deficient number, since it is larger than the sum of its proper divisors (1733986229).

6445642819 is a wasteful number, since it uses less digits than its factorization.

6445642819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11958546 (or 11958539 counting only the distinct ones).

The product of its digits is 1658880, while the sum is 49.

The square root of 6445642819 is about 80284.7608142417. The cubic root of 6445642819 is about 1861.0387325368.

The spelling of 6445642819 in words is "six billion, four hundred forty-five million, six hundred forty-two thousand, eight hundred nineteen".