1988988009 has 4 divisors (see below), whose sum is σ = 2651984016. Its totient is φ = 1325992004.

The previous prime is 1988987983. The next prime is 1988988041. The reversal of 1988988009 is 9008898891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1988988009 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1988988409) 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, 331497999 + ... + 331498004.

It is an arithmetic number, because the mean of its divisors is an integer number (662996004).

Almost surely, 2^1988988009 is an apocalyptic number.

It is an amenable number.

1988988009 is a deficient number, since it is larger than the sum of its proper divisors (662996007).

1988988009 is an equidigital number, since it uses as much as digits as its factorization.

1988988009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662996006.

The product of its (nonzero) digits is 2985984, while the sum is 60.

The square root of 1988988009 is about 44598.0718080950. The cubic root of 1988988009 is about 1257.6044196827.

The spelling of 1988988009 in words is "one billion, nine hundred eighty-eight million, nine hundred eighty-eight thousand, nine".