20278985 has 16 divisors (see below), whose sum is σ = 26732160. Its totient is φ = 14699520.

The previous prime is 20278967. The next prime is 20278987. The reversal of 20278985 is 58987202.

It is a happy number.

It is not a de Polignac number, because 20278985 - 2⁸ = 20278729 is a prime.

It is a super-2 number, since 2×20278985² = 822474465260450, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20278987) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2456 + ... + 6825.

It is an arithmetic number, because the mean of its divisors is an integer number (1670760).

Almost surely, 2^20278985 is an apocalyptic number.

It is an amenable number.

20278985 is a deficient number, since it is larger than the sum of its proper divisors (6453175).

20278985 is a wasteful number, since it uses less digits than its factorization.

20278985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9328.

The product of its (nonzero) digits is 80640, while the sum is 41.

The square root of 20278985 is about 4503.2194039376. The cubic root of 20278985 is about 272.6980744331.

The spelling of 20278985 in words is "twenty million, two hundred seventy-eight thousand, nine hundred eighty-five".