20742871 has 4 divisors (see below), whose sum is σ = 20752200. Its totient is φ = 20733544.

The previous prime is 20742857. The next prime is 20742881. The reversal of 20742871 is 17824702.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20742871 - 2¹¹ = 20740823 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 (20742811) 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, 825 + ... + 6493.

It is an arithmetic number, because the mean of its divisors is an integer number (5188050).

Almost surely, 2^20742871 is an apocalyptic number.

20742871 is a deficient number, since it is larger than the sum of its proper divisors (9329).

20742871 is an equidigital number, since it uses as much as digits as its factorization.

20742871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9328.

The product of its (nonzero) digits is 6272, while the sum is 31.

The square root of 20742871 is about 4554.4342129402. The cubic root of 20742871 is about 274.7617595052.

The spelling of 20742871 in words is "twenty million, seven hundred forty-two thousand, eight hundred seventy-one".