19998705 has 16 divisors (see below), whose sum is σ = 32054400. Its totient is φ = 10647168.

The previous prime is 19998701. The next prime is 19998721. The reversal of 19998705 is 50789991.

It is not a de Polignac number, because 19998705 - 2² = 19998701 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19998701) 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, 13596 + ... + 14994.

It is an arithmetic number, because the mean of its divisors is an integer number (2003400).

Almost surely, 2^19998705 is an apocalyptic number.

19998705 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19998705 is a deficient number, since it is larger than the sum of its proper divisors (12055695).

19998705 is a wasteful number, since it uses less digits than its factorization.

19998705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2360.

The product of its (nonzero) digits is 204120, while the sum is 48.

The square root of 19998705 is about 4471.9911672542. The cubic root of 19998705 is about 271.4359029150.

The spelling of 19998705 in words is "nineteen million, nine hundred ninety-eight thousand, seven hundred five".