21408650 has 12 divisors (see below), whose sum is σ = 39820182. Its totient is φ = 8563440.

The previous prime is 21408623. The next prime is 21408659. The reversal of 21408650 is 5680412.

It can be written as a sum of positive squares in 3 ways, for example, as 20511841 + 896809 = 4529^2 + 947^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21408659) 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, 214037 + ... + 214136.

Almost surely, 2^21408650 is an apocalyptic number.

21408650 is a deficient number, since it is larger than the sum of its proper divisors (18411532).

21408650 is a wasteful number, since it uses less digits than its factorization.

21408650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428185 (or 428180 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 21408650 is about 4626.9482383100. The cubic root of 21408650 is about 277.6705117689.

The spelling of 21408650 in words is "twenty-one million, four hundred eight thousand, six hundred fifty".