216640253 has 4 divisors (see below), whose sum is σ = 218785308. Its totient is φ = 214495200.

The previous prime is 216640213. The next prime is 216640273. The reversal of 216640253 is 352046612.

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

It can be written as a sum of positive squares in 2 ways, for example, as 173106649 + 43533604 = 13157^2 + 6598^2 .

It is a cyclic number.

It is not a de Polignac number, because 216640253 - 2²² = 212445949 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 (216640213) 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, 1072376 + ... + 1072577.

It is an arithmetic number, because the mean of its divisors is an integer number (54696327).

Almost surely, 2^216640253 is an apocalyptic number.

It is an amenable number.

216640253 is a deficient number, since it is larger than the sum of its proper divisors (2145055).

216640253 is a wasteful number, since it uses less digits than its factorization.

216640253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2145054.

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 216640253 is about 14718.7041888884. The cubic root of 216640253 is about 600.5922420751.

Adding to 216640253 its reverse (352046612), we get a palindrome (568686865).

The spelling of 216640253 in words is "two hundred sixteen million, six hundred forty thousand, two hundred fifty-three".