21011053 has 6 divisors (see below), whose sum is σ = 24441486. Its totient is φ = 18009432.

The previous prime is 21011033. The next prime is 21011063. The reversal of 21011053 is 35011012.

It can be written as a sum of positive squares in only one way, i.e., 13972644 + 7038409 = 3738^2 + 2653^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21011053 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 (21011033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 214350 + ... + 214447.

It is an arithmetic number, because the mean of its divisors is an integer number (4073581).

Almost surely, 2^21011053 is an apocalyptic number.

It is an amenable number.

21011053 is a deficient number, since it is larger than the sum of its proper divisors (3430433).

21011053 is an equidigital number, since it uses as much as digits as its factorization.

21011053 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 428811 (or 428804 counting only the distinct ones).

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

The square root of 21011053 is about 4583.7815174810. The cubic root of 21011053 is about 275.9408129404.

Adding to 21011053 its reverse (35011012), we get a palindrome (56022065).

The spelling of 21011053 in words is "twenty-one million, eleven thousand, fifty-three".