20406447 has 6 divisors (see below), whose sum is σ = 29475992. Its totient is φ = 13604292.

The previous prime is 20406439. The next prime is 20406461. The reversal of 20406447 is 74460402.

It is not a de Polignac number, because 20406447 - 2³ = 20406439 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20406447.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20426447) 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, 1133683 + ... + 1133700.

Almost surely, 2^20406447 is an apocalyptic number.

20406447 is a deficient number, since it is larger than the sum of its proper divisors (9069545).

20406447 is a wasteful number, since it uses less digits than its factorization.

20406447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2267389 (or 2267386 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 27.

The square root of 20406447 is about 4517.3495547721. The cubic root of 20406447 is about 273.2682224778.

Adding to 20406447 its reverse (74460402), we get a palindrome (94866849).

The spelling of 20406447 in words is "twenty million, four hundred six thousand, four hundred forty-seven".