20051009 has 16 divisors (see below), whose sum is σ = 23393664. Its totient is φ = 17001600.

The previous prime is 20050981. The next prime is 20051047. The reversal of 20051009 is 90015002.

It is not a de Polignac number, because 20051009 - 2¹² = 20046913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20051309) by changing a digit.

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, 9407 + ... + 11339.

It is an arithmetic number, because the mean of its divisors is an integer number (1462104).

Almost surely, 2^20051009 is an apocalyptic number.

It is an amenable number.

20051009 is a deficient number, since it is larger than the sum of its proper divisors (3342655).

20051009 is a wasteful number, since it uses less digits than its factorization.

20051009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2008.

The product of its (nonzero) digits is 90, while the sum is 17.

The square root of 20051009 is about 4477.8353029114. The cubic root of 20051009 is about 271.6723319648.

The spelling of 20051009 in words is "twenty million, fifty-one thousand, nine".