20705915 has 16 divisors (see below), whose sum is σ = 27695520. Its totient is φ = 14768640.

The previous prime is 20705899. The next prime is 20705917. The reversal of 20705915 is 51950702.

It is not a de Polignac number, because 20705915 - 2⁴ = 20705899 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20705917) 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 in 15 ways as a sum of consecutive naturals, for example, 4796 + ... + 8025.

It is an arithmetic number, because the mean of its divisors is an integer number (1730970).

Almost surely, 2^20705915 is an apocalyptic number.

20705915 is a deficient number, since it is larger than the sum of its proper divisors (6989605).

20705915 is a wasteful number, since it uses less digits than its factorization.

20705915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12862.

The product of its (nonzero) digits is 3150, while the sum is 29.

The square root of 20705915 is about 4550.3752592506. The cubic root of 20705915 is about 274.5984884417.

The spelling of 20705915 in words is "twenty million, seven hundred five thousand, nine hundred fifteen".