21251053 has 2 divisors, whose sum is σ = 21251054. Its totient is φ = 21251052.

The previous prime is 21251023. The next prime is 21251077. The reversal of 21251053 is 35015212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20912329 + 338724 = 4573^2 + 582^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21251053 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21251053.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21251023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10625526 + 10625527.

It is an arithmetic number, because the mean of its divisors is an integer number (10625527).

Almost surely, 2^21251053 is an apocalyptic number.

It is an amenable number.

21251053 is a deficient number, since it is larger than the sum of its proper divisors (1).

21251053 is an equidigital number, since it uses as much as digits as its factorization.

21251053 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 21251053 is about 4609.8864411176. The cubic root of 21251053 is about 276.9874878682.

Adding to 21251053 its reverse (35015212), we get a palindrome (56266265).

The spelling of 21251053 in words is "twenty-one million, two hundred fifty-one thousand, fifty-three".