21117650 has 12 divisors (see below), whose sum is σ = 39278922. Its totient is φ = 8447040.

The previous prime is 21117647. The next prime is 21117667. The reversal of 21117650 is 5671112.

It can be written as a sum of positive squares in 3 ways, for example, as 12397441 + 8720209 = 3521^2 + 2953^2 .

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 5 ways as a sum of consecutive naturals, for example, 211127 + ... + 211226.

Almost surely, 2^21117650 is an apocalyptic number.

21117650 is a deficient number, since it is larger than the sum of its proper divisors (18161272).

21117650 is a wasteful number, since it uses less digits than its factorization.

21117650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422365 (or 422360 counting only the distinct ones).

The product of its (nonzero) digits is 420, while the sum is 23.

The square root of 21117650 is about 4595.3944335606. The cubic root of 21117650 is about 276.4066766140.

Adding to 21117650 its reverse (5671112), we get a palindrome (26788762).

The spelling of 21117650 in words is "twenty-one million, one hundred seventeen thousand, six hundred fifty".