644158228000 has 192 divisors, whose sum is σ = 1810364774400. Its totient is φ = 220662758400.

The previous prime is 644158227959. The next prime is 644158228031. The reversal of 644158228000 is 822851446.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34402641 + ... + 34421359.

It is an arithmetic number, because the mean of its divisors is an integer number (9428983200).

Almost surely, 2^644158228000 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 644158228000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (905182387200).

644158228000 is an abundant number, since it is smaller than the sum of its proper divisors (1166206546400).

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

644158228000 is a wasteful number, since it uses less digits than its factorization.

644158228000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19980 (or 19962 counting only the distinct ones).

The product of its (nonzero) digits is 122880, while the sum is 40.

The spelling of 644158228000 in words is "six hundred forty-four billion, one hundred fifty-eight million, two hundred twenty-eight thousand".