20408647 has 6 divisors (see below), whose sum is σ = 23740728. Its totient is φ = 17493084.

The previous prime is 20408639. The next prime is 20408677. The reversal of 20408647 is 74680402.

It is not a de Polignac number, because 20408647 - 2³ = 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 5 ways as a sum of consecutive naturals, for example, 208203 + ... + 208300.

It is an arithmetic number, because the mean of its divisors is an integer number (3956788).

Almost surely, 2^20408647 is an apocalyptic number.

20408647 is a deficient number, since it is larger than the sum of its proper divisors (3332081).

20408647 is an equidigital number, since it uses as much as digits as its factorization.

20408647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 416517 (or 416510 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 31.

The square root of 20408647 is about 4517.5930538286. The cubic root of 20408647 is about 273.2780423889.

The spelling of 20408647 in words is "twenty million, four hundred eight thousand, six hundred forty-seven".