216840053 has 4 divisors (see below), whose sum is σ = 216871488. Its totient is φ = 216808620.

The previous prime is 216840023. The next prime is 216840061. The reversal of 216840053 is 350048612.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216840053 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 216839998 and 216840025.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216840023) 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, 383 + ... + 20828.

It is an arithmetic number, because the mean of its divisors is an integer number (54217872).

Almost surely, 2^216840053 is an apocalyptic number.

It is an amenable number.

216840053 is a deficient number, since it is larger than the sum of its proper divisors (31435).

216840053 is a wasteful number, since it uses less digits than its factorization.

216840053 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31434.

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 216840053 is about 14725.4899069607. The cubic root of 216840053 is about 600.7768206672.

Adding to 216840053 its reverse (350048612), we get a palindrome (566888665).

The spelling of 216840053 in words is "two hundred sixteen million, eight hundred forty thousand, fifty-three".