216947389 has 2 divisors, whose sum is σ = 216947390. Its totient is φ = 216947388.

The previous prime is 216947333. The next prime is 216947429. The reversal of 216947389 is 983749612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 119530489 + 97416900 = 10933^2 + 9870^2 .

It is a cyclic number.

It is not a de Polignac number, because 216947389 - 2⁷ = 216947261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216947329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108473694 + 108473695.

It is an arithmetic number, because the mean of its divisors is an integer number (108473695).

Almost surely, 2^216947389 is an apocalyptic number.

It is an amenable number.

216947389 is a deficient number, since it is larger than the sum of its proper divisors (1).

216947389 is an equidigital number, since it uses as much as digits as its factorization.

216947389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 49.

The square root of 216947389 is about 14729.1340207088. The cubic root of 216947389 is about 600.8759326514.

The spelling of 216947389 in words is "two hundred sixteen million, nine hundred forty-seven thousand, three hundred eighty-nine".