21255544 has 16 divisors (see below), whose sum is σ = 40606920. Its totient is φ = 10427040.

The previous prime is 21255541. The next prime is 21255557. The reversal of 21255544 is 44555212.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255541) 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, 24642 + ... + 25489.

Almost surely, 2^21255544 is an apocalyptic number.

It is an amenable number.

21255544 is a deficient number, since it is larger than the sum of its proper divisors (19351376).

21255544 is a wasteful number, since it uses less digits than its factorization.

21255544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50190 (or 50186 counting only the distinct ones).

The product of its digits is 8000, while the sum is 28.

The square root of 21255544 is about 4610.3735206597. The cubic root of 21255544 is about 277.0069984808.

The spelling of 21255544 in words is "twenty-one million, two hundred fifty-five thousand, five hundred forty-four".