1663861920 has 384 divisors, whose sum is σ = 6415718400. Its totient is φ = 354004992.

The previous prime is 1663861919. The next prime is 1663861933. The reversal of 1663861920 is 291683661.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4277086 + ... + 4277474.

It is an arithmetic number, because the mean of its divisors is an integer number (16707600).

Almost surely, 2^1663861920 is an apocalyptic number.

1663861920 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 1663861920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3207859200).

1663861920 is an abundant number, since it is smaller than the sum of its proper divisors (4751856480).

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

1663861920 is a wasteful number, since it uses less digits than its factorization.

1663861920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500 (or 492 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 42.

The square root of 1663861920 is about 40790.4635913837. The cubic root of 1663861920 is about 1184.9656490959.

The spelling of 1663861920 in words is "one billion, six hundred sixty-three million, eight hundred sixty-one thousand, nine hundred twenty".