21357853 has 8 divisors (see below), whose sum is σ = 24051456. Its totient is φ = 18789600.

The previous prime is 21357827. The next prime is 21357857. The reversal of 21357853 is 35875312.

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 21357853 - 2¹³ = 21349661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21357857) 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, 30976 + ... + 31657.

It is an arithmetic number, because the mean of its divisors is an integer number (3006432).

Almost surely, 2^21357853 is an apocalyptic number.

It is an amenable number.

21357853 is a deficient number, since it is larger than the sum of its proper divisors (2693603).

21357853 is a wasteful number, since it uses less digits than its factorization.

21357853 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62675.

The product of its digits is 25200, while the sum is 34.

The square root of 21357853 is about 4621.4557230379. The cubic root of 21357853 is about 277.4507252282.

The spelling of 21357853 in words is "twenty-one million, three hundred fifty-seven thousand, eight hundred fifty-three".