1998769985 has 16 divisors (see below), whose sum is σ = 2549014272. Its totient is φ = 1499385600.

The previous prime is 1998769979. The next prime is 1998770009. The reversal of 1998769985 is 5899678991.

It is a happy number.

It is not a de Polignac number, because 1998769985 - 2²⁰ = 1997721409 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20351 + ... + 66420.

It is an arithmetic number, because the mean of its divisors is an integer number (159313392).

Almost surely, 2^1998769985 is an apocalyptic number.

It is an amenable number.

1998769985 is a deficient number, since it is larger than the sum of its proper divisors (550244287).

1998769985 is a wasteful number, since it uses less digits than its factorization.

1998769985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87064.

The product of its digits is 88179840, while the sum is 71.

The square root of 1998769985 is about 44707.6054491850. The cubic root of 1998769985 is about 1259.6627099623.

The spelling of 1998769985 in words is "one billion, nine hundred ninety-eight million, seven hundred sixty-nine thousand, nine hundred eighty-five".