21157593 has 8 divisors (see below), whose sum is σ = 29120256. Its totient is φ = 13650000.

The previous prime is 21157573. The next prime is 21157597. The reversal of 21157593 is 39575112.

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

It is not a de Polignac number, because 21157593 - 2⁶ = 21157529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21157597) 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 7 ways as a sum of consecutive naturals, for example, 113658 + ... + 113843.

It is an arithmetic number, because the mean of its divisors is an integer number (3640032).

Almost surely, 2^21157593 is an apocalyptic number.

It is an amenable number.

21157593 is a deficient number, since it is larger than the sum of its proper divisors (7962663).

21157593 is a wasteful number, since it uses less digits than its factorization.

21157593 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227535.

The product of its digits is 9450, while the sum is 33.

The square root of 21157593 is about 4599.7383621245. The cubic root of 21157593 is about 276.5808367490.

The spelling of 21157593 in words is "twenty-one million, one hundred fifty-seven thousand, five hundred ninety-three".