21249927 has 6 divisors (see below), whose sum is σ = 30694352. Its totient is φ = 14166612.

The previous prime is 21249919. The next prime is 21249929. The reversal of 21249927 is 72994212.

It is not a de Polignac number, because 21249927 - 2³ = 21249919 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21249891 and 21249900.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21249929) 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 5 ways as a sum of consecutive naturals, for example, 1180543 + ... + 1180560.

Almost surely, 2^21249927 is an apocalyptic number.

21249927 is a deficient number, since it is larger than the sum of its proper divisors (9444425).

21249927 is a wasteful number, since it uses less digits than its factorization.

21249927 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2361109 (or 2361106 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 21249927 is about 4609.7643106779. The cubic root of 21249927 is about 276.9825956648.

The spelling of 21249927 in words is "twenty-one million, two hundred forty-nine thousand, nine hundred twenty-seven".