21311053 has 2 divisors, whose sum is σ = 21311054. Its totient is φ = 21311052.

The previous prime is 21311051. The next prime is 21311057. The reversal of 21311053 is 35011312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12299049 + 9012004 = 3507^2 + 3002^2 .

It is a cyclic number.

It is not a de Polignac number, because 21311053 - 2¹ = 21311051 is a prime.

Together with 21311051, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21311051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655526 + 10655527.

It is an arithmetic number, because the mean of its divisors is an integer number (10655527).

Almost surely, 2^21311053 is an apocalyptic number.

It is an amenable number.

21311053 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311053 is an equidigital number, since it uses as much as digits as its factorization.

21311053 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90, while the sum is 16.

The square root of 21311053 is about 4616.3896066082. The cubic root of 21311053 is about 277.2479241061.

Adding to 21311053 its reverse (35011312), we get a palindrome (56322365).

The spelling of 21311053 in words is "twenty-one million, three hundred eleven thousand, fifty-three".