20878509 has 8 divisors (see below), whose sum is σ = 27871200. Its totient is φ = 13902416.

The previous prime is 20878477. The next prime is 20878513. The reversal of 20878509 is 90587802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20878509 - 2⁵ = 20878477 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20878519) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 834 + ... + 6515.

It is an arithmetic number, because the mean of its divisors is an integer number (3483900).

Almost surely, 2^20878509 is an apocalyptic number.

It is an amenable number.

20878509 is a deficient number, since it is larger than the sum of its proper divisors (6992691).

20878509 is an equidigital number, since it uses as much as digits as its factorization.

20878509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8299.

The product of its (nonzero) digits is 40320, while the sum is 39.

The square root of 20878509 is about 4569.3007123629. The cubic root of 20878509 is about 275.3593495081.

The spelling of 20878509 in words is "twenty million, eight hundred seventy-eight thousand, five hundred nine".