21361028 has 12 divisors (see below), whose sum is σ = 40257420. Its totient is φ = 9858912.

The previous prime is 21361013. The next prime is 21361031. The reversal of 21361028 is 82016312.

It can be written as a sum of positive squares in 2 ways, for example, as 10125124 + 11235904 = 3182^2 + 3352^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21360994 and 21361012.

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 3 ways as a sum of consecutive naturals, for example, 205343 + ... + 205446.

It is an arithmetic number, because the mean of its divisors is an integer number (3354785).

Almost surely, 2^21361028 is an apocalyptic number.

It is an amenable number.

21361028 is a deficient number, since it is larger than the sum of its proper divisors (18896392).

21361028 is a wasteful number, since it uses less digits than its factorization.

21361028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410806 (or 410804 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 21361028 is about 4621.7992167553. The cubic root of 21361028 is about 277.4644729022.

The spelling of 21361028 in words is "twenty-one million, three hundred sixty-one thousand, twenty-eight".