20392987 has 2 divisors, whose sum is σ = 20392988. Its totient is φ = 20392986.

The previous prime is 20392963. The next prime is 20393027. The reversal of 20392987 is 78929302.

It is an a-pointer prime, because the next prime (20393027) can be obtained adding 20392987 to its sum of digits (40).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20392987 is a prime.

It is not a weakly prime, because it can be changed into another prime (20392907) 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 as a sum of consecutive naturals, namely, 10196493 + 10196494.

It is an arithmetic number, because the mean of its divisors is an integer number (10196494).

Almost surely, 2^20392987 is an apocalyptic number.

20392987 is a deficient number, since it is larger than the sum of its proper divisors (1).

20392987 is an equidigital number, since it uses as much as digits as its factorization.

20392987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 20392987 is about 4515.8594973715. The cubic root of 20392987 is about 273.2081271024.

The spelling of 20392987 in words is "twenty million, three hundred ninety-two thousand, nine hundred eighty-seven".