20809730 has 16 divisors (see below), whose sum is σ = 37618560. Its totient is φ = 8288112.

The previous prime is 20809729. The next prime is 20809757. The reversal of 20809730 is 3790802.

It is a junction number, because it is equal to n+sod(n) for n = 20809693 and 20809702.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1964 + ... + 6743.

It is an arithmetic number, because the mean of its divisors is an integer number (2351160).

Almost surely, 2^20809730 is an apocalyptic number.

20809730 is a deficient number, since it is larger than the sum of its proper divisors (16808830).

20809730 is a wasteful number, since it uses less digits than its factorization.

20809730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8953.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 20809730 is about 4561.7682974917. The cubic root of 20809730 is about 275.0566494865.

The spelling of 20809730 in words is "twenty million, eight hundred nine thousand, seven hundred thirty".