221731340 has 48 divisors (see below), whose sum is σ = 501155424. Its totient is φ = 82099200.

The previous prime is 221731337. The next prime is 221731423. The reversal of 221731340 is 43137122.

221731340 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15395 + ... + 26085.

It is an arithmetic number, because the mean of its divisors is an integer number (10440738).

Almost surely, 2^221731340 is an apocalyptic number.

221731340 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 221731340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (250577712).

221731340 is an abundant number, since it is smaller than the sum of its proper divisors (279424084).

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

221731340 is a wasteful number, since it uses less digits than its factorization.

221731340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10778 (or 10776 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 221731340 is about 14890.6460571729. The cubic root of 221731340 is about 605.2605393791.

Adding to 221731340 its reverse (43137122), we get a palindrome (264868462).

The spelling of 221731340 in words is "two hundred twenty-one million, seven hundred thirty-one thousand, three hundred forty".