1281136428 has 72 divisors (see below), whose sum is σ = 3804602256. Its totient is φ = 358358400.

The previous prime is 1281136421. The next prime is 1281136447. The reversal of 1281136428 is 8246311821.

1281136428 is a `hidden beast` number, since 1 + 2 + 8 + 1 + 1 + 3 + 642 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1281136392 and 1281136401.

It is not an unprimeable number, because it can be changed into a prime (1281136421) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 119283 + ... + 129578.

It is an arithmetic number, because the mean of its divisors is an integer number (52841698).

Almost surely, 2^1281136428 is an apocalyptic number.

1281136428 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1281136428 is an abundant number, since it is smaller than the sum of its proper divisors (2523465828).

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

1281136428 is a wasteful number, since it uses less digits than its factorization.

1281136428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248895 (or 248890 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 1281136428 is about 35792.9661805221. The cubic root of 1281136428 is about 1086.0882786922.

The spelling of 1281136428 in words is "one billion, two hundred eighty-one million, one hundred thirty-six thousand, four hundred twenty-eight".