21050311 has 2 divisors, whose sum is σ = 21050312. Its totient is φ = 21050310.

The previous prime is 21050303. The next prime is 21050339. The reversal of 21050311 is 11305012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21050311 - 2³ = 21050303 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21050291 and 21050300.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21050371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525155 + 10525156.

It is an arithmetic number, because the mean of its divisors is an integer number (10525156).

Almost surely, 2^21050311 is an apocalyptic number.

21050311 is a deficient number, since it is larger than the sum of its proper divisors (1).

21050311 is an equidigital number, since it uses as much as digits as its factorization.

21050311 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30, while the sum is 13.

The square root of 21050311 is about 4588.0617912142. The cubic root of 21050311 is about 276.1125661052.

Adding to 21050311 its reverse (11305012), we get a palindrome (32355323).

The spelling of 21050311 in words is "twenty-one million, fifty thousand, three hundred eleven".