1663844400 has 360 divisors, whose sum is σ = 6318059904. Its totient is φ = 403660800.

The previous prime is 1663844393. The next prime is 1663844419. The reversal of 1663844400 is 44483661.

1663844400 is a `hidden beast` number, since 16 + 638 + 4 + 4 + 4 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

It is a super-2 number, since 2×1663844400² = 5536756374822720000, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1896762 + ... + 1897638.

Almost surely, 2^1663844400 is an apocalyptic number.

1663844400 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 1663844400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3159029952).

1663844400 is an abundant number, since it is smaller than the sum of its proper divisors (4654215504).

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

1663844400 is a wasteful number, since it uses less digits than its factorization.

1663844400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 949 (or 935 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 1663844400 is about 40790.2488347399. The cubic root of 1663844400 is about 1184.9614899625.

The spelling of 1663844400 in words is "one billion, six hundred sixty-three million, eight hundred forty-four thousand, four hundred".