20671057 has 4 divisors (see below), whose sum is σ = 22550256. Its totient is φ = 18791860.

The previous prime is 20671033. The next prime is 20671073. The reversal of 20671057 is 75017602.

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.

It is a cyclic number.

It is not a de Polignac number, because 20671057 - 2¹¹ = 20669009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20671097) 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 3 ways as a sum of consecutive naturals, for example, 939583 + ... + 939604.

It is an arithmetic number, because the mean of its divisors is an integer number (5637564).

Almost surely, 2^20671057 is an apocalyptic number.

It is an amenable number.

20671057 is a deficient number, since it is larger than the sum of its proper divisors (1879199).

20671057 is a wasteful number, since it uses less digits than its factorization.

20671057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1879198.

The product of its (nonzero) digits is 2940, while the sum is 28.

The square root of 20671057 is about 4546.5434123079. The cubic root of 20671057 is about 274.4443081743. Note that the first 3 decimals are identical.

Adding to 20671057 its reverse (75017602), we get a palindrome (95688659).

The spelling of 20671057 in words is "twenty million, six hundred seventy-one thousand, fifty-seven".