20487985 has 16 divisors (see below), whose sum is σ = 29577600. Its totient is φ = 13309056.

The previous prime is 20487977. The next prime is 20487989. The reversal of 20487985 is 58978402.

It is a cyclic number.

It is not a de Polignac number, because 20487985 - 2³ = 20487977 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20487989) 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 in 15 ways as a sum of consecutive naturals, for example, 14740 + ... + 16069.

It is an arithmetic number, because the mean of its divisors is an integer number (1848600).

Almost surely, 2^20487985 is an apocalyptic number.

It is an amenable number.

20487985 is a deficient number, since it is larger than the sum of its proper divisors (9089615).

20487985 is a wasteful number, since it uses less digits than its factorization.

20487985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30840.

The product of its (nonzero) digits is 161280, while the sum is 43.

The square root of 20487985 is about 4526.3655398123. The cubic root of 20487985 is about 273.6317045510.

The spelling of 20487985 in words is "twenty million, four hundred eighty-seven thousand, nine hundred eighty-five".