20459987 has 2 divisors, whose sum is σ = 20459988. Its totient is φ = 20459986.

The previous prime is 20459981. The next prime is 20460007. The reversal of 20459987 is 78995402.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20459987 - 2¹² = 20455891 is a prime.

It is a super-2 number, since 2×20459987² = 837222136080338, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20459981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10229993 + 10229994.

It is an arithmetic number, because the mean of its divisors is an integer number (10229994).

Almost surely, 2^20459987 is an apocalyptic number.

20459987 is a deficient number, since it is larger than the sum of its proper divisors (1).

20459987 is an equidigital number, since it uses as much as digits as its factorization.

20459987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 44.

The square root of 20459987 is about 4523.2717141467. The cubic root of 20459987 is about 273.5070032865.

The spelling of 20459987 in words is "twenty million, four hundred fifty-nine thousand, nine hundred eighty-seven".