21105650 has 12 divisors (see below), whose sum is σ = 39256602. Its totient is φ = 8442240.

The previous prime is 21105641. The next prime is 21105659. The reversal of 21105650 is 5650112.

It is an interprime number because it is at equal distance from previous prime (21105641) and next prime (21105659).

It can be written as a sum of positive squares in 3 ways, for example, as 20151121 + 954529 = 4489^2 + 977^2 .

It is a hoax number, since the sum of its digits (20) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105659) 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, 211007 + ... + 211106.

Almost surely, 2^21105650 is an apocalyptic number.

21105650 is a deficient number, since it is larger than the sum of its proper divisors (18150952).

21105650 is a wasteful number, since it uses less digits than its factorization.

21105650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422125 (or 422120 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 20.

The square root of 21105650 is about 4594.0885929638. The cubic root of 21105650 is about 276.3543111190.

Adding to 21105650 its reverse (5650112), we get a palindrome (26755762).

The spelling of 21105650 in words is "twenty-one million, one hundred five thousand, six hundred fifty".