216440377 has 6 divisors (see below), whose sum is σ = 217184478. Its totient is φ = 215698752.

The previous prime is 216440363. The next prime is 216440387. The reversal of 216440377 is 773044612.

It can be written as a sum of positive squares in 3 ways, for example, as 77105961 + 139334416 = 8781^2 + 11804^2 .

It is not a de Polignac number, because 216440377 - 2²⁷ = 82222649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216440317) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 120913 + ... + 122689.

It is an arithmetic number, because the mean of its divisors is an integer number (36197413).

Almost surely, 2^216440377 is an apocalyptic number.

It is an amenable number.

216440377 is a deficient number, since it is larger than the sum of its proper divisors (744101).

216440377 is an frugal number, since it uses more digits than its factorization.

216440377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2475 (or 2126 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 34.

The square root of 216440377 is about 14711.9127580339. The cubic root of 216440377 is about 600.4074796860.

Adding to 216440377 its reverse (773044612), we get a palindrome (989484989).

The spelling of 216440377 in words is "two hundred sixteen million, four hundred forty thousand, three hundred seventy-seven".