221342531 has 2 divisors, whose sum is σ = 221342532. Its totient is φ = 221342530.

The previous prime is 221342521. The next prime is 221342551. The reversal of 221342531 is 135243122.

221342531 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221342531 is a prime.

It is a super-2 number, since 2×221342531² = 97985032058971922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221342497 and 221342506.

It is not a weakly prime, because it can be changed into another prime (221342521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110671265 + 110671266.

It is an arithmetic number, because the mean of its divisors is an integer number (110671266).

Almost surely, 2^221342531 is an apocalyptic number.

221342531 is a deficient number, since it is larger than the sum of its proper divisors (1).

221342531 is an equidigital number, since it uses as much as digits as its factorization.

221342531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 23.

The square root of 221342531 is about 14877.5848510435. The cubic root of 221342531 is about 604.9065547911.

Adding to 221342531 its reverse (135243122), we get a palindrome (356585653).

It can be divided in two parts, 2213 and 42531, that added together give a palindrome (44744).

The spelling of 221342531 in words is "two hundred twenty-one million, three hundred forty-two thousand, five hundred thirty-one".