1998569664 has 378 divisors, whose sum is σ = 7233064020. Its totient is φ = 525837312.

The previous prime is 1998569653. The next prime is 1998569707. The reversal of 1998569664 is 4669658991.

1998569664 is a `hidden beast` number, since 1 + 9 + 9 + 8 + 569 + 6 + 64 = 666.

It is a super-2 number, since 2×1998569664² = 7988561403722145792, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 4769647 + ... + 4770065.

It is an arithmetic number, because the mean of its divisors is an integer number (19135090).

Almost surely, 2^1998569664 is an apocalyptic number.

1998569664 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1998569664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3616532010).

1998569664 is an abundant number, since it is smaller than the sum of its proper divisors (5234494356).

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

1998569664 is a wasteful number, since it uses less digits than its factorization.

1998569664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 477 (or 444 counting only the distinct ones).

The product of its digits is 25194240, while the sum is 63.

The square root of 1998569664 is about 44705.3650471618. The cubic root of 1998569664 is about 1259.6206265266.

The spelling of 1998569664 in words is "one billion, nine hundred ninety-eight million, five hundred sixty-nine thousand, six hundred sixty-four".