20871355 has 4 divisors (see below), whose sum is σ = 25045632. Its totient is φ = 16697080.

The previous prime is 20871353. The next prime is 20871379. The reversal of 20871355 is 55317802.

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

It is not a de Polignac number, because 20871355 - 2¹ = 20871353 is a prime.

It is a super-2 number, since 2×20871355² = 871226919072050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20871353) 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, 2087131 + ... + 2087140.

It is an arithmetic number, because the mean of its divisors is an integer number (6261408).

Almost surely, 2^20871355 is an apocalyptic number.

20871355 is a deficient number, since it is larger than the sum of its proper divisors (4174277).

20871355 is an equidigital number, since it uses as much as digits as its factorization.

20871355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4174276.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 20871355 is about 4568.5178121575. The cubic root of 20871355 is about 275.3278953810.

The spelling of 20871355 in words is "twenty million, eight hundred seventy-one thousand, three hundred fifty-five".