21253044 has 12 divisors (see below), whose sum is σ = 49590464. Its totient is φ = 7084344.

The previous prime is 21253033. The next prime is 21253093. The reversal of 21253044 is 44035212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 21253044.

It is a congruent number.

It is an unprimeable number.

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, 885532 + ... + 885555.

Almost surely, 2^21253044 is an apocalyptic number.

It is an amenable number.

21253044 is an abundant number, since it is smaller than the sum of its proper divisors (28337420).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21253044 is a wasteful number, since it uses less digits than its factorization.

21253044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1771094 (or 1771092 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 21253044 is about 4610.1023849802. The cubic root of 21253044 is about 276.9961378688.

Adding to 21253044 its reverse (44035212), we get a palindrome (65288256).

The spelling of 21253044 in words is "twenty-one million, two hundred fifty-three thousand, forty-four".