21131445 has 8 divisors (see below), whose sum is σ = 33810336. Its totient is φ = 11270096.

The previous prime is 21131423. The next prime is 21131449. The reversal of 21131445 is 54413112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21131445 - 2⁷ = 21131317 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131449) 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 7 ways as a sum of consecutive naturals, for example, 704367 + ... + 704396.

It is an arithmetic number, because the mean of its divisors is an integer number (4226292).

Almost surely, 2^21131445 is an apocalyptic number.

It is an amenable number.

21131445 is a deficient number, since it is larger than the sum of its proper divisors (12678891).

21131445 is a wasteful number, since it uses less digits than its factorization.

21131445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1408771.

The product of its digits is 480, while the sum is 21.

The square root of 21131445 is about 4596.8951478144. The cubic root of 21131445 is about 276.4668506094.

Adding to 21131445 its reverse (54413112), we get a palindrome (75544557).

The spelling of 21131445 in words is "twenty-one million, one hundred thirty-one thousand, four hundred forty-five".