1205661075840 has 320 divisors, whose sum is σ = 4636838550960. Its totient is φ = 296777945088.

The previous prime is 1205661075799. The next prime is 1205661075841. The reversal of 1205661075840 is 485701665021.

1205661075840 is a `hidden beast` number, since 1 + 2 + 0 + 5 + 6 + 61 + 0 + 7 + 584 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (320).

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 (1205661075841) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 220594 + ... + 1568433.

Almost surely, 2^{1205661075840} is an apocalyptic number.

1205661075840 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 1205661075840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2318419275480).

1205661075840 is an abundant number, since it is smaller than the sum of its proper divisors (3431177475120).

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

1205661075840 is a wasteful number, since it uses less digits than its factorization.

1205661075840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1789071 (or 1789050 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The spelling of 1205661075840 in words is "one trillion, two hundred five billion, six hundred sixty-one million, seventy-five thousand, eight hundred forty".