21126851 has 2 divisors, whose sum is σ = 21126852. Its totient is φ = 21126850.

The previous prime is 21126827. The next prime is 21126887. The reversal of 21126851 is 15862112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21126851 - 2²² = 16932547 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21126851.

It is not a weakly prime, because it can be changed into another prime (21126451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10563425 + 10563426.

It is an arithmetic number, because the mean of its divisors is an integer number (10563426).

Almost surely, 2^21126851 is an apocalyptic number.

21126851 is a deficient number, since it is larger than the sum of its proper divisors (1).

21126851 is an equidigital number, since it uses as much as digits as its factorization.

21126851 is an evil number, because the sum of its binary digits is even.

The product of its digits is 960, while the sum is 26.

The square root of 21126851 is about 4596.3954355560. The cubic root of 21126851 is about 276.4468144222.

Adding to 21126851 its reverse (15862112), we get a palindrome (36988963).

The spelling of 21126851 in words is "twenty-one million, one hundred twenty-six thousand, eight hundred fifty-one".