1986805985 has 16 divisors (see below), whose sum is σ = 2395738560. Its totient is φ = 1581750720.

The previous prime is 1986805981. The next prime is 1986805991. The reversal of 1986805985 is 5895086891.

It is not a de Polignac number, because 1986805985 - 2² = 1986805981 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1986805981) 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, 1768634 + ... + 1769756.

It is an arithmetic number, because the mean of its divisors is an integer number (149733660).

Almost surely, 2^1986805985 is an apocalyptic number.

It is an amenable number.

1986805985 is a deficient number, since it is larger than the sum of its proper divisors (408932575).

1986805985 is a wasteful number, since it uses less digits than its factorization.

1986805985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2528.

The product of its (nonzero) digits is 6220800, while the sum is 59.

The square root of 1986805985 is about 44573.6018849722. The cubic root of 1986805985 is about 1257.1443654393.

The spelling of 1986805985 in words is "one billion, nine hundred eighty-six million, eight hundred five thousand, nine hundred eighty-five".