216403311 has 4 divisors (see below), whose sum is σ = 288537752. Its totient is φ = 144268872.

The previous prime is 216403283. The next prime is 216403321. The reversal of 216403311 is 113304612.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 216403311 - 2⁶ = 216403247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216403321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36067216 + ... + 36067221.

It is an arithmetic number, because the mean of its divisors is an integer number (72134438).

Almost surely, 2^216403311 is an apocalyptic number.

216403311 is a deficient number, since it is larger than the sum of its proper divisors (72134441).

216403311 is an equidigital number, since it uses as much as digits as its factorization.

216403311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72134440.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 216403311 is about 14710.6529766697. The cubic root of 216403311 is about 600.3732039277.

Adding to 216403311 its reverse (113304612), we get a palindrome (329707923).

The spelling of 216403311 in words is "two hundred sixteen million, four hundred three thousand, three hundred eleven".