640261191600 has 360 divisors, whose sum is σ = 2240830431840. Its totient is φ = 169287045120.

The previous prime is 640261191571. The next prime is 640261191631. The reversal of 640261191600 is 6191162046.

640261191600 is a `hidden beast` number, since 6 + 40 + 2 + 6 + 1 + 1 + 9 + 1 + 600 = 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 (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, 216815724 + ... + 216818676.

Almost surely, 2^640261191600 is an apocalyptic number.

640261191600 is a gapful number since it is divisible by the number (60) 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 640261191600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1120415215920).

640261191600 is an abundant number, since it is smaller than the sum of its proper divisors (1600569240240).

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

640261191600 is a wasteful number, since it uses less digits than its factorization.

640261191600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3469 (or 3455 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The spelling of 640261191600 in words is "six hundred forty billion, two hundred sixty-one million, one hundred ninety-one thousand, six hundred".