216441591 has 4 divisors (see below), whose sum is σ = 288588792. Its totient is φ = 144294392.

The previous prime is 216441581. The next prime is 216441607. The reversal of 216441591 is 195144612.

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

It is a cyclic number.

It is not a de Polignac number, because 216441591 - 2⁹ = 216441079 is a prime.

It is a super-2 number, since 2×216441591² = 93693924629222562, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216441541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36073596 + ... + 36073601.

It is an arithmetic number, because the mean of its divisors is an integer number (72147198).

Almost surely, 2^216441591 is an apocalyptic number.

216441591 is a deficient number, since it is larger than the sum of its proper divisors (72147201).

216441591 is an equidigital number, since it uses as much as digits as its factorization.

216441591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72147200.

The product of its digits is 8640, while the sum is 33.

The square root of 216441591 is about 14711.9540170570. The cubic root of 216441591 is about 600.4086022327.

The spelling of 216441591 in words is "two hundred sixteen million, four hundred forty-one thousand, five hundred ninety-one".