21425593 has 24 divisors (see below), whose sum is σ = 26778600. Its totient is φ = 17090304.

The previous prime is 21425587. The next prime is 21425603. The reversal of 21425593 is 39552412.

It can be written as a sum of positive squares in 4 ways, for example, as 1605289 + 19820304 = 1267^2 + 4452^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21425593 is a prime.

It is a super-3 number, since 3×21425593³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21425533) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 240693 + ... + 240781.

It is an arithmetic number, because the mean of its divisors is an integer number (1115775).

Almost surely, 2^21425593 is an apocalyptic number.

It is an amenable number.

21425593 is a deficient number, since it is larger than the sum of its proper divisors (5353007).

21425593 is an frugal number, since it uses more digits than its factorization.

21425593 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154 (or 113 counting only the distinct ones).

The product of its digits is 10800, while the sum is 31.

The square root of 21425593 is about 4628.7787806289. The cubic root of 21425593 is about 277.7437427752.

The spelling of 21425593 in words is "twenty-one million, four hundred twenty-five thousand, five hundred ninety-three".