1001660400 has 360 divisors, whose sum is σ = 3966777360. Its totient is φ = 231874560.

The previous prime is 1001660399. The next prime is 1001660441. The reversal of 1001660400 is 40661001.

1001660400 is a `hidden beast` number, since 1 + 0 + 0 + 1 + 660 + 4 + 0 + 0 = 666.

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

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

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, 794971 + ... + 796229.

It is an arithmetic number, because the mean of its divisors is an integer number (11018826).

Almost surely, 2^1001660400 is an apocalyptic number.

1001660400 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 1001660400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1983388680).

1001660400 is an abundant number, since it is smaller than the sum of its proper divisors (2965116960).

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

1001660400 is a wasteful number, since it uses less digits than its factorization.

1001660400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1313 (or 1299 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 1001660400 is about 31649.0189421410. The cubic root of 1001660400 is about 1000.5531606236.

The spelling of 1001660400 in words is "one billion, one million, six hundred sixty thousand, four hundred".