220644386640 has 160 divisors (see below), whose sum is σ = 761628216960. Its totient is φ = 58712242176.

The previous prime is 220644386527. The next prime is 220644386647. The reversal of 220644386640 is 46683446022.

220644386640 is a `hidden beast` number, since 2 + 206 + 4 + 4 + 386 + 64 + 0 = 666.

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 (220644386647) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 899352 + ... + 1118088.

It is an arithmetic number, because the mean of its divisors is an integer number (4760176356).

Almost surely, 2^220644386640 is an apocalyptic number.

220644386640 is a gapful number since it is divisible by the number (20) 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 220644386640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (380814108480).

220644386640 is an abundant number, since it is smaller than the sum of its proper divisors (540983830320).

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

220644386640 is a wasteful number, since it uses less digits than its factorization.

220644386640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219226 (or 219214 counting only the distinct ones).

The product of its (nonzero) digits is 1327104, while the sum is 45.

The spelling of 220644386640 in words is "two hundred twenty billion, six hundred forty-four million, three hundred eighty-six thousand, six hundred forty".