1663643520 has 768 divisors, whose sum is σ = 7454453760. Its totient is φ = 334540800.

The previous prime is 1663643519. The next prime is 1663643573. The reversal of 1663643520 is 253463661.

1663643520 is a `hidden beast` number, since 1 + 6 + 6 + 3 + 643 + 5 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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 95 ways as a sum of consecutive naturals, for example, 53665905 + ... + 53665935.

It is an arithmetic number, because the mean of its divisors is an integer number (9706320).

Almost surely, 2^1663643520 is an apocalyptic number.

1663643520 is a gapful number since it is divisible by the number (10) 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 1663643520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3727226880).

1663643520 is an abundant number, since it is smaller than the sum of its proper divisors (5790810240).

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

1663643520 is a wasteful number, since it uses less digits than its factorization.

1663643520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96 (or 59 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 36.

The square root of 1663643520 is about 40787.7864072077. The cubic root of 1663643520 is about 1184.9138002779.

The spelling of 1663643520 in words is "one billion, six hundred sixty-three million, six hundred forty-three thousand, five hundred twenty".