221431340 has 24 divisors (see below), whose sum is σ = 500776080. Its totient is φ = 81759168.

The previous prime is 221431337. The next prime is 221431351. The reversal of 221431340 is 43134122.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 425570 + ... + 426089.

It is an arithmetic number, because the mean of its divisors is an integer number (20865670).

Almost surely, 2^221431340 is an apocalyptic number.

221431340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221431340 is an abundant number, since it is smaller than the sum of its proper divisors (279344740).

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

221431340 is a wasteful number, since it uses less digits than its factorization.

221431340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 851681 (or 851679 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 221431340 is about 14880.5692095430. The cubic root of 221431340 is about 604.9874459522.

Adding to 221431340 its reverse (43134122), we get a palindrome (264565462).

The spelling of 221431340 in words is "two hundred twenty-one million, four hundred thirty-one thousand, three hundred forty".