216387331 has 2 divisors, whose sum is σ = 216387332. Its totient is φ = 216387330.

The previous prime is 216387323. The next prime is 216387343. The reversal of 216387331 is 133783612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 216387331 - 2³ = 216387323 is a prime.

It is a super-2 number, since 2×216387331² = 93646954034607122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (216387131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108193665 + 108193666.

It is an arithmetic number, because the mean of its divisors is an integer number (108193666).

Almost surely, 2^216387331 is an apocalyptic number.

216387331 is a deficient number, since it is larger than the sum of its proper divisors (1).

216387331 is an equidigital number, since it uses as much as digits as its factorization.

216387331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 34.

The square root of 216387331 is about 14710.1098228395. The cubic root of 216387331 is about 600.3584256573.

The spelling of 216387331 in words is "two hundred sixteen million, three hundred eighty-seven thousand, three hundred thirty-one".