20853971 has 4 divisors (see below), whose sum is σ = 20940744. Its totient is φ = 20767200.

The previous prime is 20853941. The next prime is 20853991. The reversal of 20853971 is 17935802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20853971 - 2¹⁰ = 20852947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20853941) 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, 43025 + ... + 43506.

It is an arithmetic number, because the mean of its divisors is an integer number (5235186).

Almost surely, 2^20853971 is an apocalyptic number.

20853971 is a deficient number, since it is larger than the sum of its proper divisors (86773).

20853971 is an equidigital number, since it uses as much as digits as its factorization.

20853971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86772.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 20853971 is about 4566.6148293895. The cubic root of 20853971 is about 275.2514328545.

The spelling of 20853971 in words is "twenty million, eight hundred fifty-three thousand, nine hundred seventy-one".