221311778688 has 2304 divisors, whose sum is σ = 970333344000. Its totient is φ = 48910417920.

The previous prime is 221311778663. The next prime is 221311778761. The reversal of 221311778688 is 886877113122.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 5981399406 + ... + 5981399442.

It is an arithmetic number, because the mean of its divisors is an integer number (421151625).

Almost surely, 2^221311778688 is an apocalyptic number.

221311778688 is a gapful number since it is divisible by the number (28) 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 221311778688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (485166672000).

221311778688 is an abundant number, since it is smaller than the sum of its proper divisors (749021565312).

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

221311778688 is a wasteful number, since it uses less digits than its factorization.

221311778688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130 (or 92 counting only the distinct ones).

The product of its digits is 1806336, while the sum is 54.

It can be divided in two parts, 221311 and 778688, that added together give a palindrome (999999).

The spelling of 221311778688 in words is "two hundred twenty-one billion, three hundred eleven million, seven hundred seventy-eight thousand, six hundred eighty-eight".