21161268 has 18 divisors (see below), whose sum is σ = 53491074. Its totient is φ = 7053744.

The previous prime is 21161237. The next prime is 21161279. The reversal of 21161268 is 86216112.

It can be written as a sum of positive squares in only one way, i.e., 19820304 + 1340964 = 4452^2 + 1158^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 293871 + ... + 293942.

Almost surely, 2^21161268 is an apocalyptic number.

It is an amenable number.

21161268 is an abundant number, since it is smaller than the sum of its proper divisors (32329806).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21161268 is a wasteful number, since it uses less digits than its factorization.

21161268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 587823 (or 587818 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 21161268 is about 4600.1378240222. The cubic root of 21161268 is about 276.5968495304.

The spelling of 21161268 in words is "twenty-one million, one hundred sixty-one thousand, two hundred sixty-eight".