216531253 has 2 divisors, whose sum is σ = 216531254. Its totient is φ = 216531252.

The previous prime is 216531251. The next prime is 216531307. The reversal of 216531253 is 352135612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 160326244 + 56205009 = 12662^2 + 7497^2 .

It is a cyclic number.

It is not a de Polignac number, because 216531253 - 2¹ = 216531251 is a prime.

Together with 216531251, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216531251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108265626 + 108265627.

It is an arithmetic number, because the mean of its divisors is an integer number (108265627).

Almost surely, 2^216531253 is an apocalyptic number.

It is an amenable number.

216531253 is a deficient number, since it is larger than the sum of its proper divisors (1).

216531253 is an equidigital number, since it uses as much as digits as its factorization.

216531253 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5400, while the sum is 28.

The square root of 216531253 is about 14715.0009514101. Note that the first 3 decimals coincide. The cubic root of 216531253 is about 600.4914981985.

Subtracting from 216531253 its sum of digits (28), we obtain a square (216531225 = 14715²).

Adding to 216531253 its reverse (352135612), we get a palindrome (568666865).

The spelling of 216531253 in words is "two hundred sixteen million, five hundred thirty-one thousand, two hundred fifty-three".