21050911 has 16 divisors (see below), whose sum is σ = 25588224. Its totient is φ = 16926624.

The previous prime is 21050873. The next prime is 21050921. The reversal of 21050911 is 11905012.

It is a cyclic number.

It is not a de Polignac number, because 21050911 - 2⁹ = 21050399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21050921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7300 + ... + 9766.

It is an arithmetic number, because the mean of its divisors is an integer number (1599264).

Almost surely, 2^21050911 is an apocalyptic number.

21050911 is a deficient number, since it is larger than the sum of its proper divisors (4537313).

21050911 is a wasteful number, since it uses less digits than its factorization.

21050911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2550.

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

The square root of 21050911 is about 4588.1271778363. The cubic root of 21050911 is about 276.1151894388.

Adding to 21050911 its reverse (11905012), we get a palindrome (32955923).

The spelling of 21050911 in words is "twenty-one million, fifty thousand, nine hundred eleven".