21393441 has 12 divisors (see below), whose sum is σ = 31898880. Its totient is φ = 13802040.

The previous prime is 21393433. The next prime is 21393457. The reversal of 21393441 is 14439312.

21393441 is a `hidden beast` number, since 213 + 9 + 3 + 441 = 666.

It is not a de Polignac number, because 21393441 - 2³ = 21393433 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21393461) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38061 + ... + 38618.

It is an arithmetic number, because the mean of its divisors is an integer number (2658240).

Almost surely, 2^21393441 is an apocalyptic number.

It is an amenable number.

21393441 is a deficient number, since it is larger than the sum of its proper divisors (10505439).

21393441 is a wasteful number, since it uses less digits than its factorization.

21393441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76716 (or 76713 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 21393441 is about 4625.3044224137. The cubic root of 21393441 is about 277.6047425393.

The spelling of 21393441 in words is "twenty-one million, three hundred ninety-three thousand, four hundred forty-one".