221440731 has 16 divisors (see below), whose sum is σ = 301536000. Its totient is φ = 144499680.

The previous prime is 221440729. The next prime is 221440741. The reversal of 221440731 is 137044122.

It is a happy number.

It is not a de Polignac number, because 221440731 - 2¹ = 221440729 is a prime.

It is a super-2 number, since 2×221440731² = 98071994691628722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (221440741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 77946 + ... + 80736.

It is an arithmetic number, because the mean of its divisors is an integer number (18846000).

Almost surely, 2^221440731 is an apocalyptic number.

221440731 is a deficient number, since it is larger than the sum of its proper divisors (80095269).

221440731 is a wasteful number, since it uses less digits than its factorization.

221440731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3346.

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 221440731 is about 14880.8847519225. The cubic root of 221440731 is about 604.9959984254.

Adding to 221440731 its reverse (137044122), we get a palindrome (358484853).

It can be divided in two parts, 22 and 1440731, that added together give a triangular number (1440753 = T₁₆₉₇).

The spelling of 221440731 in words is "two hundred twenty-one million, four hundred forty thousand, seven hundred thirty-one".