20705407 has 2 divisors, whose sum is σ = 20705408. Its totient is φ = 20705406.

The previous prime is 20705387. The next prime is 20705411. The reversal of 20705407 is 70450702.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20705407 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20705107) 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, 10352703 + 10352704.

It is an arithmetic number, because the mean of its divisors is an integer number (10352704).

Almost surely, 2^20705407 is an apocalyptic number.

20705407 is a deficient number, since it is larger than the sum of its proper divisors (1).

20705407 is an equidigital number, since it uses as much as digits as its factorization.

20705407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1960, while the sum is 25.

The square root of 20705407 is about 4550.3194393361. The cubic root of 20705407 is about 274.5962427521.

It can be divided in two parts, 20705 and 407, that added together give a palindrome (21112).

The spelling of 20705407 in words is "twenty million, seven hundred five thousand, four hundred seven".