642218444478 has 128 divisors (see below), whose sum is σ = 1618390771200. Its totient is φ = 187139828736.

The previous prime is 642218444477. The next prime is 642218444513. The reversal of 642218444478 is 874444812246.

It is a happy number.

It is a super-3 number, since 3×642218444478³ (a number of 36 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642218444477) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 48583726 + ... + 48596942.

It is an arithmetic number, because the mean of its divisors is an integer number (12643677900).

Almost surely, 2^642218444478 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642218444478, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (809195385600).

642218444478 is an abundant number, since it is smaller than the sum of its proper divisors (976172326722).

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

642218444478 is a wasteful number, since it uses less digits than its factorization.

642218444478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16903 (or 16897 counting only the distinct ones).

The product of its digits is 11010048, while the sum is 54.

The spelling of 642218444478 in words is "six hundred forty-two billion, two hundred eighteen million, four hundred forty-four thousand, four hundred seventy-eight".