21380011 has 2 divisors, whose sum is σ = 21380012. Its totient is φ = 21380010.

The previous prime is 21379993. The next prime is 21380027. The reversal of 21380011 is 11008312.

It is an a-pointer prime, because the next prime (21380027) can be obtained adding 21380011 to its sum of digits (16).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21380011 - 2⁵ = 21379979 is a prime.

It is not a weakly prime, because it can be changed into another prime (21380071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10690005 + 10690006.

It is an arithmetic number, because the mean of its divisors is an integer number (10690006).

Almost surely, 2^21380011 is an apocalyptic number.

21380011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21380011 is an equidigital number, since it uses as much as digits as its factorization.

21380011 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 16.

The square root of 21380011 is about 4623.8523981632. The cubic root of 21380011 is about 277.5466404304.

Adding to 21380011 its reverse (11008312), we get a palindrome (32388323).

The spelling of 21380011 in words is "twenty-one million, three hundred eighty thousand, eleven".