6440424612221 has 8 divisors (see below), whose sum is σ = 6461562279744. Its totient is φ = 6419289694720.

The previous prime is 6440424612169. The next prime is 6440424612229. The reversal of 6440424612221 is 1222164240446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6440424612221 - 2²² = 6440420417917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440424612229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4057730 + ... + 5417196.

It is an arithmetic number, because the mean of its divisors is an integer number (807695284968).

Almost surely, 2^{6440424612221} is an apocalyptic number.

It is an amenable number.

6440424612221 is a deficient number, since it is larger than the sum of its proper divisors (21137667523).

6440424612221 is a wasteful number, since it uses less digits than its factorization.

6440424612221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1375011.

The product of its (nonzero) digits is 147456, while the sum is 38.

Adding to 6440424612221 its reverse (1222164240446), we get a palindrome (7662588852667).

The spelling of 6440424612221 in words is "six trillion, four hundred forty billion, four hundred twenty-four million, six hundred twelve thousand, two hundred twenty-one".