21905011 has 2 divisors, whose sum is σ = 21905012. Its totient is φ = 21905010.

The previous prime is 21904963. The next prime is 21905053. The reversal of 21905011 is 11050912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21905011 - 2¹¹ = 21902963 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21905011.

It is not a weakly prime, because it can be changed into another prime (21905071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10952505 + 10952506.

It is an arithmetic number, because the mean of its divisors is an integer number (10952506).

Almost surely, 2^21905011 is an apocalyptic number.

21905011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21905011 is an equidigital number, since it uses as much as digits as its factorization.

21905011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90, while the sum is 19.

The square root of 21905011 is about 4680.2789446784. The cubic root of 21905011 is about 279.8000741194.

Adding to 21905011 its reverse (11050912), we get a palindrome (32955923).

The spelling of 21905011 in words is "twenty-one million, nine hundred five thousand, eleven".