21865122 has 12 divisors (see below), whose sum is σ = 47374470. Its totient is φ = 7288368.

The previous prime is 21865121. The next prime is 21865133. The reversal of 21865122 is 22156812.

It is a happy number.

21865122 is a `hidden beast` number, since 2 + 1 + 8 + 651 + 2 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 18326961 + 3538161 = 4281^2 + 1881^2 .

It is not an unprimeable number, because it can be changed into a prime (21865121) by changing a digit.

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, 607347 + ... + 607382.

Almost surely, 2^21865122 is an apocalyptic number.

21865122 is an abundant number, since it is smaller than the sum of its proper divisors (25509348).

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

21865122 is a wasteful number, since it uses less digits than its factorization.

21865122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1214737 (or 1214734 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 21865122 is about 4676.0156116078. The cubic root of 21865122 is about 279.6301323847.

The spelling of 21865122 in words is "twenty-one million, eight hundred sixty-five thousand, one hundred twenty-two".