21671593 has 4 divisors (see below), whose sum is σ = 21711760. Its totient is φ = 21631428.

The previous prime is 21671581. The next prime is 21671597. The reversal of 21671593 is 39517612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21671593 - 2⁵ = 21671561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21671597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19263 + ... + 20356.

It is an arithmetic number, because the mean of its divisors is an integer number (5427940).

Almost surely, 2^21671593 is an apocalyptic number.

It is an amenable number.

21671593 is a deficient number, since it is larger than the sum of its proper divisors (40167).

21671593 is an equidigital number, since it uses as much as digits as its factorization.

21671593 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40166.

The product of its digits is 11340, while the sum is 34.

The square root of 21671593 is about 4655.2758242665. The cubic root of 21671593 is about 278.8026807603.

The spelling of 21671593 in words is "twenty-one million, six hundred seventy-one thousand, five hundred ninety-three".