21254121 has 12 divisors (see below), whose sum is σ = 35086272. Its totient is φ = 12145176.

The previous prime is 21254119. The next prime is 21254143. The reversal of 21254121 is 12145212.

It is not a de Polignac number, because 21254121 - 2¹ = 21254119 is a prime.

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21254094 and 21254103.

It is not an unprimeable number, because it can be changed into a prime (21254161) 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 in 11 ways as a sum of consecutive naturals, for example, 168621 + ... + 168746.

It is an arithmetic number, because the mean of its divisors is an integer number (2923856).

Almost surely, 2^21254121 is an apocalyptic number.

21254121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21254121 is a deficient number, since it is larger than the sum of its proper divisors (13832151).

21254121 is a wasteful number, since it uses less digits than its factorization.

21254121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 337380 (or 337377 counting only the distinct ones).

The product of its digits is 160, while the sum is 18.

The square root of 21254121 is about 4610.2191921860. The cubic root of 21254121 is about 277.0008167249. Note that the first 3 decimals are identical.

Adding to 21254121 its reverse (12145212), we get a palindrome (33399333).

The spelling of 21254121 in words is "twenty-one million, two hundred fifty-four thousand, one hundred twenty-one".