221340431 has 16 divisors (see below), whose sum is σ = 249359040. Its totient is φ = 194937600.

The previous prime is 221340409. The next prime is 221340439. The reversal of 221340431 is 134043122.

221340431 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a de Polignac number, because none of the positive numbers 2^k-221340431 is a prime.

It is a super-2 number, since 2×221340431² = 97983172790531522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221340439) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 169481 + ... + 170781.

It is an arithmetic number, because the mean of its divisors is an integer number (15584940).

Almost surely, 2^221340431 is an apocalyptic number.

221340431 is a deficient number, since it is larger than the sum of its proper divisors (28018609).

221340431 is a wasteful number, since it uses less digits than its factorization.

221340431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1906.

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

The square root of 221340431 is about 14877.5142749049. The cubic root of 221340431 is about 604.9046417565.

Adding to 221340431 its reverse (134043122), we get a palindrome (355383553).

The spelling of 221340431 in words is "two hundred twenty-one million, three hundred forty thousand, four hundred thirty-one".