20857853 has 4 divisors (see below), whose sum is σ = 20875680. Its totient is φ = 20840028.

The previous prime is 20857843. The next prime is 20857867. The reversal of 20857853 is 35875802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 35875802 = 2 ⋅17937901.

It is a cyclic number.

It is not a de Polignac number, because 20857853 - 2⁸ = 20857597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20857843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7025 + ... + 9542.

It is an arithmetic number, because the mean of its divisors is an integer number (5218920).

Almost surely, 2^20857853 is an apocalyptic number.

It is an amenable number.

20857853 is a deficient number, since it is larger than the sum of its proper divisors (17827).

20857853 is a wasteful number, since it uses less digits than its factorization.

20857853 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17826.

The product of its (nonzero) digits is 67200, while the sum is 38.

The square root of 20857853 is about 4567.0398509319. The cubic root of 20857853 is about 275.2685112927.

The spelling of 20857853 in words is "twenty million, eight hundred fifty-seven thousand, eight hundred fifty-three".