216405841 has 4 divisors (see below), whose sum is σ = 218109952. Its totient is φ = 214701732.

The previous prime is 216405811. The next prime is 216405851. The reversal of 216405841 is 148504612.

216405841 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 216405841 - 2¹¹ = 216403793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216405811) 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, 851865 + ... + 852118.

It is an arithmetic number, because the mean of its divisors is an integer number (54527488).

Almost surely, 2^216405841 is an apocalyptic number.

It is an amenable number.

216405841 is a deficient number, since it is larger than the sum of its proper divisors (1704111).

216405841 is a wasteful number, since it uses less digits than its factorization.

216405841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1704110.

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 216405841 is about 14710.7389685223. The cubic root of 216405841 is about 600.3755435997.

Adding to 216405841 its product of nonzero digits (7680), we get a square (216413521 = 14711²).

The spelling of 216405841 in words is "two hundred sixteen million, four hundred five thousand, eight hundred forty-one".