21385263 has 8 divisors (see below), whose sum is σ = 28597248. Its totient is φ = 14215064.

The previous prime is 21385253. The next prime is 21385283. The reversal of 21385263 is 36258312.

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 21385263 - 2¹² = 21381167 is a prime.

It is a super-3 number, since 3×21385263³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21385263.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21385253) 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 7 ways as a sum of consecutive naturals, for example, 9231 + ... + 11312.

It is an arithmetic number, because the mean of its divisors is an integer number (3574656).

Almost surely, 2^21385263 is an apocalyptic number.

21385263 is a deficient number, since it is larger than the sum of its proper divisors (7211985).

21385263 is a wasteful number, since it uses less digits than its factorization.

21385263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20893.

The product of its digits is 8640, while the sum is 30.

The square root of 21385263 is about 4624.4202879929. The cubic root of 21385263 is about 277.5693650151.

The spelling of 21385263 in words is "twenty-one million, three hundred eighty-five thousand, two hundred sixty-three".