21852813 has 8 divisors (see below), whose sum is σ = 29254176. Its totient is φ = 14510000.

The previous prime is 21852797. The next prime is 21852827. The reversal of 21852813 is 31825812.

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 21852813 - 2⁴ = 21852797 is a prime.

It is a super-3 number, since 3×21852813³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21852013) 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, 13758 + ... + 15263.

It is an arithmetic number, because the mean of its divisors is an integer number (3656772).

Almost surely, 2^21852813 is an apocalyptic number.

It is an amenable number.

21852813 is a deficient number, since it is larger than the sum of its proper divisors (7401363).

21852813 is a wasteful number, since it uses less digits than its factorization.

21852813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29275.

The product of its digits is 3840, while the sum is 30.

The square root of 21852813 is about 4674.6992416625. The cubic root of 21852813 is about 279.5776498147.

The spelling of 21852813 in words is "twenty-one million, eight hundred fifty-two thousand, eight hundred thirteen".