1280749140 has 72 divisors (see below), whose sum is σ = 4238121888. Its totient is φ = 310484160.

The previous prime is 1280749133. The next prime is 1280749147. The reversal of 1280749140 is 419470821.

1280749140 is a `hidden beast` number, since 128 + 0 + 7 + 491 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (1280749133) and next prime (1280749147).

It is a super-2 number, since 2×1280749140² = 3280636719221479200, which contains 22 as substring.

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 = 1280749095 and 1280749104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1280749147) 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, 321442 + ... + 325401.

It is an arithmetic number, because the mean of its divisors is an integer number (58862804).

Almost surely, 2^1280749140 is an apocalyptic number.

1280749140 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1280749140 is an abundant number, since it is smaller than the sum of its proper divisors (2957372748).

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

1280749140 is a wasteful number, since it uses less digits than its factorization.

1280749140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 646869 (or 646864 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 1280749140 is about 35787.5556583570. Note that the first 3 decimals coincide. The cubic root of 1280749140 is about 1085.9788260373.

The spelling of 1280749140 in words is "one billion, two hundred eighty million, seven hundred forty-nine thousand, one hundred forty".