21050123 has 4 divisors (see below), whose sum is σ = 21216000. Its totient is φ = 20884248.

The previous prime is 21050111. The next prime is 21050137. The reversal of 21050123 is 32105012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21050123 - 2⁶ = 21050059 is a prime.

It is a super-3 number, since 3×21050123³ (a number of 23 digits) contains 333 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21050098 and 21050107.

It is not an unprimeable number, because it can be changed into a prime (21050173) 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, 82748 + ... + 83001.

It is an arithmetic number, because the mean of its divisors is an integer number (5304000).

Almost surely, 2^21050123 is an apocalyptic number.

21050123 is a deficient number, since it is larger than the sum of its proper divisors (165877).

21050123 is a wasteful number, since it uses less digits than its factorization.

21050123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165876.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 21050123 is about 4588.0413032143. The cubic root of 21050123 is about 276.1117441170. Note that the first 3 decimals are identical.

Adding to 21050123 its reverse (32105012), we get a palindrome (53155135).

The spelling of 21050123 in words is "twenty-one million, fifty thousand, one hundred twenty-three".