20555287 has 4 divisors (see below), whose sum is σ = 21264120. Its totient is φ = 19846456.

The previous prime is 20555251. The next prime is 20555299. The reversal of 20555287 is 78255502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20555287 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20555237) by changing a digit.

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, 354373 + ... + 354430.

It is an arithmetic number, because the mean of its divisors is an integer number (5316030).

Almost surely, 2^20555287 is an apocalyptic number.

20555287 is a deficient number, since it is larger than the sum of its proper divisors (708833).

20555287 is an equidigital number, since it uses as much as digits as its factorization.

20555287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 708832.

The product of its (nonzero) digits is 28000, while the sum is 34.

The square root of 20555287 is about 4533.7938859194. The cubic root of 20555287 is about 273.9309991950.

The spelling of 20555287 in words is "twenty million, five hundred fifty-five thousand, two hundred eighty-seven".