105205421 has 4 divisors (see below), whose sum is σ = 105365244. Its totient is φ = 105045600.

The previous prime is 105205361. The next prime is 105205433. The reversal of 105205421 is 124502501.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 124502501 = 43 ⋅2895407.

It can be written as a sum of positive squares in 2 ways, for example, as 90992521 + 14212900 = 9539^2 + 3770^2 .

It is a cyclic number.

It is not a de Polignac number, because 105205421 - 2⁶ = 105205357 is a prime.

It is a super-2 number, since 2×105205421² = 22136361215574482, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 105205393 and 105205402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (105205481) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78920 + ... + 80241.

It is an arithmetic number, because the mean of its divisors is an integer number (26341311).

Almost surely, 2^105205421 is an apocalyptic number.

It is an amenable number.

105205421 is a deficient number, since it is larger than the sum of its proper divisors (159823).

105205421 is an equidigital number, since it uses as much as digits as its factorization.

105205421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159822.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 105205421 is about 10256.9693867146. The cubic root of 105205421 is about 472.0768526707.

Adding to 105205421 its reverse (124502501), we get a palindrome (229707922).

The spelling of 105205421 in words is "one hundred five million, two hundred five thousand, four hundred twenty-one".