20421367 has 2 divisors, whose sum is σ = 20421368. Its totient is φ = 20421366.

The previous prime is 20421347. The next prime is 20421383. The reversal of 20421367 is 76312402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20421367 - 2¹⁹ = 19897079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20421337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210683 + 10210684.

It is an arithmetic number, because the mean of its divisors is an integer number (10210684).

Almost surely, 2^20421367 is an apocalyptic number.

20421367 is a deficient number, since it is larger than the sum of its proper divisors (1).

20421367 is an equidigital number, since it uses as much as digits as its factorization.

20421367 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 20421367 is about 4519.0006638636. Note that the first 3 decimals coincide. The cubic root of 20421367 is about 273.3348054981.

Adding to 20421367 its reverse (76312402), we get a palindrome (96733769).

The spelling of 20421367 in words is "twenty million, four hundred twenty-one thousand, three hundred sixty-seven".