20405387 has 2 divisors, whose sum is σ = 20405388. Its totient is φ = 20405386.

The previous prime is 20405383. The next prime is 20405443. The reversal of 20405387 is 78350402.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20405387 - 2² = 20405383 is a prime.

It is not a weakly prime, because it can be changed into another prime (20405383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10202693 + 10202694.

It is an arithmetic number, because the mean of its divisors is an integer number (10202694).

Almost surely, 2^20405387 is an apocalyptic number.

20405387 is a deficient number, since it is larger than the sum of its proper divisors (1).

20405387 is an equidigital number, since it uses as much as digits as its factorization.

20405387 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6720, while the sum is 29.

The square root of 20405387 is about 4517.2322278138. The cubic root of 20405387 is about 273.2634908141.

Adding to 20405387 its reverse (78350402), we get a palindrome (98755789).

The spelling of 20405387 in words is "twenty million, four hundred five thousand, three hundred eighty-seven".