646522228440 has 512 divisors, whose sum is σ = 2550030336000. Its totient is φ = 143913369600.

The previous prime is 646522228439. The next prime is 646522228441. The reversal of 646522228440 is 44822225646.

646522228440 is a `hidden beast` number, since 6 + 4 + 6 + 522 + 2 + 2 + 84 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (646522228439) and next prime (646522228441).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646522228441) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 8241321 + ... + 8319399.

It is an arithmetic number, because the mean of its divisors is an integer number (4980528000).

Almost surely, 2^646522228440 is an apocalyptic number.

646522228440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646522228440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1275015168000).

646522228440 is an abundant number, since it is smaller than the sum of its proper divisors (1903508107560).

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

646522228440 is a wasteful number, since it uses less digits than its factorization.

646522228440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78168 (or 78158 counting only the distinct ones).

The product of its (nonzero) digits is 1474560, while the sum is 45.

The spelling of 646522228440 in words is "six hundred forty-six billion, five hundred twenty-two million, two hundred twenty-eight thousand, four hundred forty".