105142021 has 4 divisors (see below), whose sum is σ = 105478252. Its totient is φ = 104805792.

The previous prime is 105142013. The next prime is 105142061. The reversal of 105142021 is 120241501.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120241501 = 409 ⋅293989.

It can be written as a sum of positive squares in 2 ways, for example, as 52056225 + 53085796 = 7215^2 + 7286^2 .

It is a cyclic number.

It is not a de Polignac number, because 105142021 - 2³ = 105142013 is a prime.

It is a super-2 number, since 2×105142021² = 22109689159928882, 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 = 105141986 and 105142004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (105142061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 167646 + ... + 168271.

It is an arithmetic number, because the mean of its divisors is an integer number (26369563).

Almost surely, 2^105142021 is an apocalyptic number.

It is an amenable number.

105142021 is a deficient number, since it is larger than the sum of its proper divisors (336231).

105142021 is an equidigital number, since it uses as much as digits as its factorization.

105142021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336230.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 105142021 is about 10253.8783394382. The cubic root of 105142021 is about 471.9820043053.

Adding to 105142021 its reverse (120241501), we get a palindrome (225383522).

The spelling of 105142021 in words is "one hundred five million, one hundred forty-two thousand, twenty-one".