221947380 has 72 divisors (see below), whose sum is σ = 684684000. Its totient is φ = 58180032.

The previous prime is 221947373. The next prime is 221947403. The reversal of 221947380 is 83749122.

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

It is a congruent number.

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, 171 + ... + 21069.

It is an arithmetic number, because the mean of its divisors is an integer number (9509500).

Almost surely, 2^221947380 is an apocalyptic number.

221947380 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 221947380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (342342000).

221947380 is an abundant number, since it is smaller than the sum of its proper divisors (462736620).

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

221947380 is a wasteful number, since it uses less digits than its factorization.

221947380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20973 (or 20968 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 221947380 is about 14897.8985095214. The cubic root of 221947380 is about 605.4570505291.

The spelling of 221947380 in words is "two hundred twenty-one million, nine hundred forty-seven thousand, three hundred eighty".