221432240 has 40 divisors (see below), whose sum is σ = 518018928. Its totient is φ = 88024320.

The previous prime is 221432231. The next prime is 221432243. The reversal of 221432240 is 42234122.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×221432240² = 98064473822835200, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (221432243) by changing a digit.

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, 4550 + ... + 21530.

Almost surely, 2^221432240 is an apocalyptic number.

221432240 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 221432240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (259009464).

221432240 is an abundant number, since it is smaller than the sum of its proper divisors (296586688).

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

221432240 is a wasteful number, since it uses less digits than its factorization.

221432240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17157 (or 17151 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 221432240 is about 14880.5994502910. The cubic root of 221432240 is about 604.9882656012.

Adding to 221432240 its reverse (42234122), we get a palindrome (263666362).

The spelling of 221432240 in words is "two hundred twenty-one million, four hundred thirty-two thousand, two hundred forty".