1281685636 has 48 divisors (see below), whose sum is σ = 2811174912. Its totient is φ = 496720800.

The previous prime is 1281685627. The next prime is 1281685637. The reversal of 1281685636 is 6365861821.

It is not an unprimeable number, because it can be changed into a prime (1281685637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47935 + ... + 69721.

It is an arithmetic number, because the mean of its divisors is an integer number (58566144).

Almost surely, 2^1281685636 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1281685636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1405587456).

1281685636 is an abundant number, since it is smaller than the sum of its proper divisors (1529489276).

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

1281685636 is a wasteful number, since it uses less digits than its factorization.

1281685636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22000 (or 21998 counting only the distinct ones).

The product of its digits is 414720, while the sum is 46.

The square root of 1281685636 is about 35800.6373686280. The cubic root of 1281685636 is about 1086.2434542438.

The spelling of 1281685636 in words is "one billion, two hundred eighty-one million, six hundred eighty-five thousand, six hundred thirty-six".