20505887 has 2 divisors, whose sum is σ = 20505888. Its totient is φ = 20505886.

The previous prime is 20505869. The next prime is 20505917. The reversal of 20505887 is 78850502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20505887 - 2¹² = 20501791 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20505487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10252943 + 10252944.

It is an arithmetic number, because the mean of its divisors is an integer number (10252944).

Almost surely, 2^20505887 is an apocalyptic number.

20505887 is a deficient number, since it is larger than the sum of its proper divisors (1).

20505887 is an equidigital number, since it uses as much as digits as its factorization.

20505887 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22400, while the sum is 35.

The square root of 20505887 is about 4528.3426327962. The cubic root of 20505887 is about 273.7113793574.

The spelling of 20505887 in words is "twenty million, five hundred five thousand, eight hundred eighty-seven".