21020053 has 2 divisors, whose sum is σ = 21020054. Its totient is φ = 21020052.

The previous prime is 21020039. The next prime is 21020057. The reversal of 21020053 is 35002012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20277009 + 743044 = 4503^2 + 862^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020053 - 2⁹ = 21019541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21020057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510026 + 10510027.

It is an arithmetic number, because the mean of its divisors is an integer number (10510027).

Almost surely, 2^21020053 is an apocalyptic number.

It is an amenable number.

21020053 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020053 is an equidigital number, since it uses as much as digits as its factorization.

21020053 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60, while the sum is 13.

The square root of 21020053 is about 4584.7631345578. The cubic root of 21020053 is about 275.9802066951.

Adding to 21020053 its reverse (35002012), we get a palindrome (56022065).

The spelling of 21020053 in words is "twenty-one million, twenty thousand, fifty-three".