20280187 has 2 divisors, whose sum is σ = 20280188. Its totient is φ = 20280186.

The previous prime is 20280157. The next prime is 20280191. The reversal of 20280187 is 78108202.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20280187 - 2⁷ = 20280059 is a prime.

It is a super-2 number, since 2×20280187² = 822571969509938, which contains 22 as substring.

It is equal to p_1287244 and since 20280187 and 1287244 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (20280157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10140093 + 10140094.

It is an arithmetic number, because the mean of its divisors is an integer number (10140094).

Almost surely, 2^20280187 is an apocalyptic number.

20280187 is a deficient number, since it is larger than the sum of its proper divisors (1).

20280187 is an equidigital number, since it uses as much as digits as its factorization.

20280187 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1792, while the sum is 28.

The square root of 20280187 is about 4503.3528620351. The cubic root of 20280187 is about 272.7034622209.

Adding to 20280187 its reverse (78108202), we get a palindrome (98388389).

The spelling of 20280187 in words is "twenty million, two hundred eighty thousand, one hundred eighty-seven".