21253438 has 16 divisors (see below), whose sum is σ = 34341120. Its totient is φ = 9832536.

The previous prime is 21253423. The next prime is 21253459. The reversal of 21253438 is 83435212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4870 + ... + 8137.

It is an arithmetic number, because the mean of its divisors is an integer number (2146320).

Almost surely, 2^21253438 is an apocalyptic number.

21253438 is a deficient number, since it is larger than the sum of its proper divisors (13087682).

21253438 is a wasteful number, since it uses less digits than its factorization.

21253438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13071.

The product of its digits is 5760, while the sum is 28.

The square root of 21253438 is about 4610.1451170218. The cubic root of 21253438 is about 276.9978495578.

The spelling of 21253438 in words is "twenty-one million, two hundred fifty-three thousand, four hundred thirty-eight".