216690427 has 2 divisors, whose sum is σ = 216690428. Its totient is φ = 216690426.

The previous prime is 216690413. The next prime is 216690431. The reversal of 216690427 is 724096612.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216690427 is a prime.

It is not a weakly prime, because it can be changed into another prime (216690457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108345213 + 108345214.

It is an arithmetic number, because the mean of its divisors is an integer number (108345214).

Almost surely, 2^216690427 is an apocalyptic number.

216690427 is a deficient number, since it is larger than the sum of its proper divisors (1).

216690427 is an equidigital number, since it uses as much as digits as its factorization.

216690427 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 37.

The square root of 216690427 is about 14720.4085201464. The cubic root of 216690427 is about 600.6386043256.

The spelling of 216690427 in words is "two hundred sixteen million, six hundred ninety thousand, four hundred twenty-seven".