19906985 has 24 divisors (see below), whose sum is σ = 27998856. Its totient is φ = 13547520.

The previous prime is 19906981. The next prime is 19906993. The reversal of 19906985 is 58960991.

It can be written as a sum of positive squares in 4 ways, for example, as 582169 + 19324816 = 763^2 + 4396^2 .

It is not a de Polignac number, because 19906985 - 2² = 19906981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19906981) 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 23 ways as a sum of consecutive naturals, for example, 47075 + ... + 47495.

It is an arithmetic number, because the mean of its divisors is an integer number (1166619).

Almost surely, 2^19906985 is an apocalyptic number.

It is an amenable number.

19906985 is a deficient number, since it is larger than the sum of its proper divisors (8091871).

19906985 is a wasteful number, since it uses less digits than its factorization.

19906985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 633 (or 626 counting only the distinct ones).

The product of its (nonzero) digits is 174960, while the sum is 47.

The square root of 19906985 is about 4461.7244424101. The cubic root of 19906985 is about 271.0203050285.

The spelling of 19906985 in words is "nineteen million, nine hundred six thousand, nine hundred eighty-five".