105215021 has 2 divisors, whose sum is σ = 105215022. Its totient is φ = 105215020.

The previous prime is 105215003. The next prime is 105215039. The reversal of 105215021 is 120512501.

It is a balanced prime because it is at equal distance from previous prime (105215003) and next prime (105215039).

It can be written as a sum of positive squares in only one way, i.e., 79459396 + 25755625 = 8914^2 + 5075^2 .

It is an emirp because it is prime and its reverse (120512501) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-105215021 is a prime.

It is a super-2 number, since 2×105215021² = 22140401288060882, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (105215051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52607510 + 52607511.

It is an arithmetic number, because the mean of its divisors is an integer number (52607511).

Almost surely, 2^105215021 is an apocalyptic number.

It is an amenable number.

105215021 is a deficient number, since it is larger than the sum of its proper divisors (1).

105215021 is an equidigital number, since it uses as much as digits as its factorization.

105215021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100, while the sum is 17.

The square root of 105215021 is about 10257.4373505277. The cubic root of 105215021 is about 472.0912112462.

Adding to 105215021 its reverse (120512501), we get a palindrome (225727522).

The spelling of 105215021 in words is "one hundred five million, two hundred fifteen thousand, twenty-one".