21593121 has 16 divisors (see below), whose sum is σ = 31485888. Its totient is φ = 13054400.

The previous prime is 21593087. The next prime is 21593137. The reversal of 21593121 is 12139512.

It is a cyclic number.

It is not a de Polignac number, because 21593121 - 2⁷ = 21592993 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21593091 and 21593100.

It is not an unprimeable number, because it can be changed into a prime (21593141) 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 15 ways as a sum of consecutive naturals, for example, 25891 + ... + 26711.

It is an arithmetic number, because the mean of its divisors is an integer number (1967868).

Almost surely, 2^21593121 is an apocalyptic number.

It is an amenable number.

21593121 is a deficient number, since it is larger than the sum of its proper divisors (9892767).

21593121 is a wasteful number, since it uses less digits than its factorization.

21593121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1632.

The product of its digits is 540, while the sum is 24.

The square root of 21593121 is about 4646.8398939494. The cubic root of 21593121 is about 278.4657625355.

The spelling of 21593121 in words is "twenty-one million, five hundred ninety-three thousand, one hundred twenty-one".