6638215444 has 48 divisors (see below), whose sum is σ = 13748870016. Its totient is φ = 2745475200.

The previous prime is 6638215427. The next prime is 6638215447. The reversal of 6638215444 is 4445128366.

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 6638215444.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6638215447) 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, 53859 + ... + 127189.

It is an arithmetic number, because the mean of its divisors is an integer number (286434792).

Almost surely, 2^6638215444 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6638215444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6874435008).

6638215444 is an abundant number, since it is smaller than the sum of its proper divisors (7110654572).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6638215444 is a wasteful number, since it uses less digits than its factorization.

6638215444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73456 (or 73454 counting only the distinct ones).

The product of its digits is 552960, while the sum is 43.

The square root of 6638215444 is about 81475.2443629352. The cubic root of 6638215444 is about 1879.3908774347.

The spelling of 6638215444 in words is "six billion, six hundred thirty-eight million, two hundred fifteen thousand, four hundred forty-four".