19998685 has 16 divisors (see below), whose sum is σ = 28169856. Its totient is φ = 13341888.

The previous prime is 19998683. The next prime is 19998691. The reversal of 19998685 is 58689991.

19998685 = 22² + 23² + ... + 391².

It is not a de Polignac number, because 19998685 - 2¹ = 19998683 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 (19998683) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6427 + ... + 9016.

It is an arithmetic number, because the mean of its divisors is an integer number (1760616).

Almost surely, 2^19998685 is an apocalyptic number.

It is an amenable number.

19998685 is a deficient number, since it is larger than the sum of its proper divisors (8171171).

19998685 is a wasteful number, since it uses less digits than its factorization.

19998685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15492.

The product of its digits is 1399680, while the sum is 55.

The square root of 19998685 is about 4471.9889311133. The cubic root of 19998685 is about 271.4358124305.

The spelling of 19998685 in words is "nineteen million, nine hundred ninety-eight thousand, six hundred eighty-five".