20456905 has 16 divisors (see below), whose sum is σ = 28191744. Its totient is φ = 13959360.

The previous prime is 20456879. The next prime is 20456941. The reversal of 20456905 is 50965402.

It is not a de Polignac number, because 20456905 - 2⁹ = 20456393 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6495 + ... + 9115.

It is an arithmetic number, because the mean of its divisors is an integer number (1761984).

Almost surely, 2^20456905 is an apocalyptic number.

It is an amenable number.

20456905 is a deficient number, since it is larger than the sum of its proper divisors (7734839).

20456905 is a wasteful number, since it uses less digits than its factorization.

20456905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2856.

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 20456905 is about 4522.9310187090. The cubic root of 20456905 is about 273.4932693104.

The spelling of 20456905 in words is "twenty million, four hundred fifty-six thousand, nine hundred five".