216909773 has 2 divisors, whose sum is σ = 216909774. Its totient is φ = 216909772.

The previous prime is 216909743. The next prime is 216909827. The reversal of 216909773 is 377909612.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 153834409 + 63075364 = 12403^2 + 7942^2 .

It is a cyclic number.

It is not a de Polignac number, because 216909773 - 2⁶ = 216909709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216909703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108454886 + 108454887.

It is an arithmetic number, because the mean of its divisors is an integer number (108454887).

Almost surely, 2^216909773 is an apocalyptic number.

It is an amenable number.

216909773 is a deficient number, since it is larger than the sum of its proper divisors (1).

216909773 is an equidigital number, since it uses as much as digits as its factorization.

216909773 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 142884, while the sum is 44.

The square root of 216909773 is about 14727.8570403165. The cubic root of 216909773 is about 600.8412024869.

The spelling of 216909773 in words is "two hundred sixteen million, nine hundred nine thousand, seven hundred seventy-three".