1261889189280 has 1920 divisors, whose sum is σ = 5273232814080. Its totient is φ = 282036142080.

The previous prime is 1261889189243. The next prime is 1261889189317. The reversal of 1261889189280 is 829819881621.

1261889189280 is a `hidden beast` number, since 1 + 2 + 618 + 8 + 9 + 1 + 8 + 9 + 2 + 8 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (1261889189243) and next prime (1261889189317).

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 4555556502 + ... + 4555556778.

It is an arithmetic number, because the mean of its divisors is an integer number (2746475424).

Almost surely, 2^{1261889189280} is an apocalyptic number.

1261889189280 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 1261889189280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2636616407040).

1261889189280 is an abundant number, since it is smaller than the sum of its proper divisors (4011343624800).

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

1261889189280 is a wasteful number, since it uses less digits than its factorization.

1261889189280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 404 (or 387 counting only the distinct ones).

The product of its (nonzero) digits is 7962624, while the sum is 63.

The spelling of 1261889189280 in words is "one trillion, two hundred sixty-one billion, eight hundred eighty-nine million, one hundred eighty-nine thousand, two hundred eighty".