1281899218545 has 128 divisors (see below), whose sum is σ = 2717265346560. Its totient is φ = 566096256000.

The previous prime is 1281899218463. The next prime is 1281899218583. The reversal of 1281899218545 is 5458129981821.

1281899218545 is a `hidden beast` number, since 1 + 2 + 8 + 1 + 89 + 9 + 2 + 1 + 8 + 545 = 666.

It is not a de Polignac number, because 1281899218545 - 2²⁶ = 1281832109681 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 36411 + ... + 1601600.

It is an arithmetic number, because the mean of its divisors is an integer number (21228635520).

Almost surely, 2^{1281899218545} is an apocalyptic number.

1281899218545 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1281899218545 is an abundant number, since it is smaller than the sum of its proper divisors (1435366128015).

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

1281899218545 is a wasteful number, since it uses less digits than its factorization.

1281899218545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1638084 (or 1638078 counting only the distinct ones).

The product of its digits is 16588800, while the sum is 63.

The spelling of 1281899218545 in words is "one trillion, two hundred eighty-one billion, eight hundred ninety-nine million, two hundred eighteen thousand, five hundred forty-five".