21386853 has 6 divisors (see below), whose sum is σ = 30892134. Its totient is φ = 14257896.

The previous prime is 21386821. The next prime is 21386857. The reversal of 21386853 is 35868312.

It can be written as a sum of positive squares in only one way, i.e., 16378209 + 5008644 = 4047^2 + 2238^2 .

It is not a de Polignac number, because 21386853 - 2⁵ = 21386821 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21386857) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1188150 + ... + 1188167.

It is an arithmetic number, because the mean of its divisors is an integer number (5148689).

Almost surely, 2^21386853 is an apocalyptic number.

It is an amenable number.

21386853 is a deficient number, since it is larger than the sum of its proper divisors (9505281).

21386853 is a wasteful number, since it uses less digits than its factorization.

21386853 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2376323 (or 2376320 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 21386853 is about 4624.5921982376. The cubic root of 21386853 is about 277.5762439634.

The spelling of 21386853 in words is "twenty-one million, three hundred eighty-six thousand, eight hundred fifty-three".