21750011 has 2 divisors, whose sum is σ = 21750012. Its totient is φ = 21750010.

The previous prime is 21750007. The next prime is 21750017. The reversal of 21750011 is 11005712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21750011 - 2² = 21750007 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21750017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10875005 + 10875006.

It is an arithmetic number, because the mean of its divisors is an integer number (10875006).

Almost surely, 2^21750011 is an apocalyptic number.

21750011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21750011 is an equidigital number, since it uses as much as digits as its factorization.

21750011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 70, while the sum is 17.

The square root of 21750011 is about 4663.6907058680. The cubic root of 21750011 is about 279.1385556407.

Adding to 21750011 its reverse (11005712), we get a palindrome (32755723).

The spelling of 21750011 in words is "twenty-one million, seven hundred fifty thousand, eleven".