1988993664 has 128 divisors (see below), whose sum is σ = 6708988800. Its totient is φ = 568276992.

The previous prime is 1988993653. The next prime is 1988993683. The reversal of 1988993664 is 4663998891.

It is a happy number.

1988993664 is a `hidden beast` number, since 198 + 89 + 9 + 366 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16917 + ... + 65300.

It is an arithmetic number, because the mean of its divisors is an integer number (52413975).

Almost surely, 2^1988993664 is an apocalyptic number.

1988993664 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1988993664 is an abundant number, since it is smaller than the sum of its proper divisors (4719995136).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1988993664 is an equidigital number, since it uses as much as digits as its factorization.

1988993664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82247 (or 82229 counting only the distinct ones).

The product of its digits is 20155392, while the sum is 63.

The square root of 1988993664 is about 44598.1352076519. The cubic root of 1988993664 is about 1257.6056115361.

The spelling of 1988993664 in words is "one billion, nine hundred eighty-eight million, nine hundred ninety-three thousand, six hundred sixty-four".