20807890 has 16 divisors (see below), whose sum is σ = 37554840. Its totient is φ = 8300800.

The previous prime is 20807879. The next prime is 20807903. The reversal of 20807890 is 9870802.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 20784481 + 23409 = 4559^2 + 153^2 .

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 7 ways as a sum of consecutive naturals, for example, 1416 + ... + 6604.

Almost surely, 2^20807890 is an apocalyptic number.

20807890 is a deficient number, since it is larger than the sum of its proper divisors (16746950).

20807890 is a wasteful number, since it uses less digits than its factorization.

20807890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5597.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 20807890 is about 4561.5666168543. The cubic root of 20807890 is about 275.0485423951.

The spelling of 20807890 in words is "twenty million, eight hundred seven thousand, eight hundred ninety".