1663683840 has 864 divisors, whose sum is σ = 7595831040. Its totient is φ = 335757312.

The previous prime is 1663683809. The next prime is 1663683841. The reversal of 1663683840 is 483863661.

1663683840 is a `hidden beast` number, since 1 + 6 + 636 + 8 + 3 + 8 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1663683841) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 72334069 + ... + 72334091.

Almost surely, 2^1663683840 is an apocalyptic number.

1663683840 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 1663683840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3797915520).

1663683840 is an abundant number, since it is smaller than the sum of its proper divisors (5932147200).

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

1663683840 is a wasteful number, since it uses less digits than its factorization.

1663683840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 45.

The square root of 1663683840 is about 40788.2806698199. The cubic root of 1663683840 is about 1184.9233727089.

The spelling of 1663683840 in words is "one billion, six hundred sixty-three million, six hundred eighty-three thousand, eight hundred forty".