216231961 has 6 divisors (see below), whose sum is σ = 237676586. Its totient is φ = 196574400.

The previous prime is 216231943. The next prime is 216231971. The reversal of 216231961 is 169132612.

It can be written as a sum of positive squares in only one way, i.e., 138791961 + 77440000 = 11781^2 + 8800^2 .

It is not a de Polignac number, because 216231961 - 2¹¹ = 216229913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216231931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 893400 + ... + 893641.

Almost surely, 2^216231961 is an apocalyptic number.

It is an amenable number.

216231961 is a deficient number, since it is larger than the sum of its proper divisors (21444625).

216231961 is a wasteful number, since it uses less digits than its factorization.

216231961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1787063 (or 1787052 counting only the distinct ones).

The product of its digits is 3888, while the sum is 31.

The square root of 216231961 is about 14704.8278126607. The cubic root of 216231961 is about 600.2147018664.

The spelling of 216231961 in words is "two hundred sixteen million, two hundred thirty-one thousand, nine hundred sixty-one".