20408671 has 4 divisors (see below), whose sum is σ = 20455600. Its totient is φ = 20361744.

The previous prime is 20408639. The next prime is 20408677. The reversal of 20408671 is 17680402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17680402 = 2 ⋅8840201.

It is a cyclic number.

It is not a de Polignac number, because 20408671 - 2⁵ = 20408639 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 (20408677) 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, 22806 + ... + 23683.

It is an arithmetic number, because the mean of its divisors is an integer number (5113900).

Almost surely, 2^20408671 is an apocalyptic number.

20408671 is a deficient number, since it is larger than the sum of its proper divisors (46929).

20408671 is an equidigital number, since it uses as much as digits as its factorization.

20408671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46928.

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 20408671 is about 4517.5957101095. The cubic root of 20408671 is about 273.2781495113.

The spelling of 20408671 in words is "twenty million, four hundred eight thousand, six hundred seventy-one".