216561533 has 2 divisors, whose sum is σ = 216561534. Its totient is φ = 216561532.

The previous prime is 216561523. The next prime is 216561547. The reversal of 216561533 is 335165612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 192571129 + 23990404 = 13877^2 + 4898^2 .

It is a cyclic number.

It is not a de Polignac number, because 216561533 - 2⁸ = 216561277 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216561533.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216561503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108280766 + 108280767.

It is an arithmetic number, because the mean of its divisors is an integer number (108280767).

Almost surely, 2^216561533 is an apocalyptic number.

It is an amenable number.

216561533 is a deficient number, since it is larger than the sum of its proper divisors (1).

216561533 is an equidigital number, since it uses as much as digits as its factorization.

216561533 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16200, while the sum is 32.

The square root of 216561533 is about 14716.0297974692. The cubic root of 216561533 is about 600.5194880534.

The spelling of 216561533 in words is "two hundred sixteen million, five hundred sixty-one thousand, five hundred thirty-three".