21126516 has 24 divisors (see below), whose sum is σ = 49477344. Its totient is φ = 7016160.

The previous prime is 21126487. The next prime is 21126517. The reversal of 21126516 is 61562112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21126517) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 286 + ... + 6506.

It is an arithmetic number, because the mean of its divisors is an integer number (2061556).

Almost surely, 2^21126516 is an apocalyptic number.

It is an amenable number.

21126516 is an abundant number, since it is smaller than the sum of its proper divisors (28350828).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21126516 is a wasteful number, since it uses less digits than its factorization.

21126516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6511 (or 6509 counting only the distinct ones).

The product of its digits is 720, while the sum is 24.

The square root of 21126516 is about 4596.3589938124. The cubic root of 21126516 is about 276.4453532458.

Adding to 21126516 its reverse (61562112), we get a palindrome (82688628).

The spelling of 21126516 in words is "twenty-one million, one hundred twenty-six thousand, five hundred sixteen".