20509880 has 16 divisors (see below), whose sum is σ = 46147320. Its totient is φ = 8203936.

The previous prime is 20509843. The next prime is 20509891. The reversal of 20509880 is 8890502.

It is a super-2 number, since 2×20509880² = 841310355228800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 256334 + ... + 256413.

Almost surely, 2^20509880 is an apocalyptic number.

20509880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20509880 is an abundant number, since it is smaller than the sum of its proper divisors (25637440).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20509880 is a wasteful number, since it uses less digits than its factorization.

20509880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 512758 (or 512754 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 20509880 is about 4528.7835011182. The cubic root of 20509880 is about 273.7291443144.

The spelling of 20509880 in words is "twenty million, five hundred nine thousand, eight hundred eighty".