19681985 has 8 divisors (see below), whose sum is σ = 23647680. Its totient is φ = 15726064.

The previous prime is 19681969. The next prime is 19681999. The reversal of 19681985 is 58918691.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19681985 - 2⁴ = 19681969 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3164 + ... + 7026.

It is an arithmetic number, because the mean of its divisors is an integer number (2955960).

Almost surely, 2^19681985 is an apocalyptic number.

It is an amenable number.

19681985 is a deficient number, since it is larger than the sum of its proper divisors (3965695).

19681985 is a wasteful number, since it uses less digits than its factorization.

19681985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4887.

The product of its digits is 155520, while the sum is 47.

The square root of 19681985 is about 4436.4383237007. The cubic root of 19681985 is about 269.9953588594.

The spelling of 19681985 in words is "nineteen million, six hundred eighty-one thousand, nine hundred eighty-five".