20306421 has 12 divisors (see below), whose sum is σ = 30875520. Its totient is φ = 12825000.

The previous prime is 20306413. The next prime is 20306423. The reversal of 20306421 is 12460302.

It is a happy number.

20306421 is a `hidden beast` number, since 20 + 3 + 0 + 642 + 1 = 666.

It is not a de Polignac number, because 20306421 - 2³ = 20306413 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20306394 and 20306403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20306423) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59205 + ... + 59546.

It is an arithmetic number, because the mean of its divisors is an integer number (2572960).

Almost surely, 2^20306421 is an apocalyptic number.

It is an amenable number.

20306421 is a deficient number, since it is larger than the sum of its proper divisors (10569099).

20306421 is a wasteful number, since it uses less digits than its factorization.

20306421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118776 (or 118773 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 20306421 is about 4506.2646393660. The cubic root of 20306421 is about 272.8209992707.

Adding to 20306421 its reverse (12460302), we get a palindrome (32766723).

The spelling of 20306421 in words is "twenty million, three hundred six thousand, four hundred twenty-one".