21254111 has 4 divisors (see below), whose sum is σ = 21274752. Its totient is φ = 21233472.

The previous prime is 21254099. The next prime is 21254117. The reversal of 21254111 is 11145212.

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 21254111 - 2¹⁸ = 20991967 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21254111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21254117) 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, 8690 + ... + 10863.

It is an arithmetic number, because the mean of its divisors is an integer number (5318688).

Almost surely, 2^21254111 is an apocalyptic number.

21254111 is a deficient number, since it is larger than the sum of its proper divisors (20641).

21254111 is a wasteful number, since it uses less digits than its factorization.

21254111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20640.

The product of its digits is 80, while the sum is 17.

The square root of 21254111 is about 4610.2181076387. The cubic root of 21254111 is about 277.0007732822. Note that the first 3 decimals are identical.

Adding to 21254111 its reverse (11145212), we get a palindrome (32399323).

The spelling of 21254111 in words is "twenty-one million, two hundred fifty-four thousand, one hundred eleven".