21105369 has 6 divisors (see below), whose sum is σ = 30485546. Its totient is φ = 14070240.

The previous prime is 21105367. The next prime is 21105391. The reversal of 21105369 is 96350112.

It can be written as a sum of positive squares in only one way, i.e., 18662400 + 2442969 = 4320^2 + 1563^2 .

It is not a de Polignac number, because 21105369 - 2¹ = 21105367 is a prime.

It is a super-2 number, since 2×21105369² = 890873201252322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21105361) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1172512 + ... + 1172529.

Almost surely, 2^21105369 is an apocalyptic number.

It is an amenable number.

21105369 is a deficient number, since it is larger than the sum of its proper divisors (9380177).

21105369 is a wasteful number, since it uses less digits than its factorization.

21105369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2345047 (or 2345044 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 21105369 is about 4594.0580100822. The cubic root of 21105369 is about 276.3530846559.

The spelling of 21105369 in words is "twenty-one million, one hundred five thousand, three hundred sixty-nine".