21351053 has 2 divisors, whose sum is σ = 21351054. Its totient is φ = 21351052.

The previous prime is 21351017. The next prime is 21351073. The reversal of 21351053 is 35015312.

It is an a-pointer prime, because the next prime (21351073) can be obtained adding 21351053 to its sum of digits (20).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17197609 + 4153444 = 4147^2 + 2038^2 .

It is a cyclic number.

It is not a de Polignac number, because 21351053 - 2¹⁰ = 21350029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21351013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10675526 + 10675527.

It is an arithmetic number, because the mean of its divisors is an integer number (10675527).

Almost surely, 2^21351053 is an apocalyptic number.

It is an amenable number.

21351053 is a deficient number, since it is larger than the sum of its proper divisors (1).

21351053 is an equidigital number, since it uses as much as digits as its factorization.

21351053 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 450, while the sum is 20.

The square root of 21351053 is about 4620.7199655465. The cubic root of 21351053 is about 277.4212768063.

Adding to 21351053 its reverse (35015312), we get a palindrome (56366365).

The spelling of 21351053 in words is "twenty-one million, three hundred fifty-one thousand, fifty-three".