221686380 has 72 divisors (see below), whose sum is σ = 678678000. Its totient is φ = 58568832.

The previous prime is 221686337. The next prime is 221686393. The reversal of 221686380 is 83686122.

221686380 is a `hidden beast` number, since 2 + 2 + 16 + 8 + 638 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13971 + ... + 25269.

Almost surely, 2^221686380 is an apocalyptic number.

221686380 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 221686380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (339339000).

221686380 is an abundant number, since it is smaller than the sum of its proper divisors (456991620).

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

221686380 is a wasteful number, since it uses less digits than its factorization.

221686380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11423 (or 11418 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 221686380 is about 14889.1363080603. The cubic root of 221686380 is about 605.2196274759.

The spelling of 221686380 in words is "two hundred twenty-one million, six hundred eighty-six thousand, three hundred eighty".