19661986 has 8 divisors (see below), whose sum is σ = 29993040. Its totient is φ = 9664308.

The previous prime is 19661951. The next prime is 19661989. The reversal of 19661986 is 68916691.

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

It is not an unprimeable number, because it can be changed into a prime (19661989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83196 + ... + 83431.

It is an arithmetic number, because the mean of its divisors is an integer number (3749130).

Almost surely, 2^19661986 is an apocalyptic number.

19661986 is a deficient number, since it is larger than the sum of its proper divisors (10331054).

19661986 is a wasteful number, since it uses less digits than its factorization.

19661986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166688.

The product of its digits is 139968, while the sum is 46.

The square root of 19661986 is about 4434.1838031367. The cubic root of 19661986 is about 269.9038798227.

The spelling of 19661986 in words is "nineteen million, six hundred sixty-one thousand, nine hundred eighty-six".