221420340 has 72 divisors (see below), whose sum is σ = 674724960. Its totient is φ = 58774464.

The previous prime is 221420323. The next prime is 221420347. The reversal of 221420340 is 43024122.

221420340 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221420347) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38151 + ... + 43569.

It is an arithmetic number, because the mean of its divisors is an integer number (9371180).

Almost surely, 2^221420340 is an apocalyptic number.

221420340 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 221420340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (337362480).

221420340 is an abundant number, since it is smaller than the sum of its proper divisors (453304620).

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

221420340 is a wasteful number, since it uses less digits than its factorization.

221420340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5661 (or 5656 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 221420340 is about 14880.1995954355. The cubic root of 221420340 is about 604.9774278399.

Adding to 221420340 its reverse (43024122), we get a palindrome (264444462).

The spelling of 221420340 in words is "two hundred twenty-one million, four hundred twenty thousand, three hundred forty".