216445131 has 72 divisors (see below), whose sum is σ = 390534144. Its totient is φ = 113024160.

The previous prime is 216445129. The next prime is 216445147. The reversal of 216445131 is 131544612.

It is a happy number.

216445131 is a `hidden beast` number, since 2 + 1 + 644 + 5 + 13 + 1 = 666.

It is not a de Polignac number, because 216445131 - 2¹ = 216445129 is a prime.

It is a super-2 number, since 2×216445131² = 93696989467214322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 216445095 and 216445104.

It is not an unprimeable number, because it can be changed into a prime (216445171) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 704880 + ... + 705186.

Almost surely, 2^216445131 is an apocalyptic number.

216445131 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

216445131 is a deficient number, since it is larger than the sum of its proper divisors (174089013).

216445131 is a wasteful number, since it uses less digits than its factorization.

216445131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 389 (or 367 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 216445131 is about 14712.0743268922. The cubic root of 216445131 is about 600.4118755329.

Adding to 216445131 its reverse (131544612), we get a palindrome (347989743).

The spelling of 216445131 in words is "two hundred sixteen million, four hundred forty-five thousand, one hundred thirty-one".