20417987 has 2 divisors, whose sum is σ = 20417988. Its totient is φ = 20417986.

The previous prime is 20417977. The next prime is 20418011. The reversal of 20417987 is 78971402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20417987 - 2⁶ = 20417923 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20417987.

It is not a weakly prime, because it can be changed into another prime (20417927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10208993 + 10208994.

It is an arithmetic number, because the mean of its divisors is an integer number (10208994).

Almost surely, 2^20417987 is an apocalyptic number.

20417987 is a deficient number, since it is larger than the sum of its proper divisors (1).

20417987 is an equidigital number, since it uses as much as digits as its factorization.

20417987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 20417987 is about 4518.6266718993. The cubic root of 20417987 is about 273.3197245191.

The spelling of 20417987 in words is "twenty million, four hundred seventeen thousand, nine hundred eighty-seven".