1286723840 has 144 divisors (see below), whose sum is σ = 3208630320. Its totient is φ = 493977600.

The previous prime is 1286723831. The next prime is 1286723887. The reversal of 1286723840 is 483276821.

It can be written as a sum of positive squares in 8 ways, for example, as 44302336 + 1242421504 = 6656^2 + 35248^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4783226 + ... + 4783494.

It is an arithmetic number, because the mean of its divisors is an integer number (22282155).

Almost surely, 2^1286723840 is an apocalyptic number.

1286723840 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 1286723840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1604315160).

1286723840 is an abundant number, since it is smaller than the sum of its proper divisors (1921906480).

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

1286723840 is a wasteful number, since it uses less digits than its factorization.

1286723840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428 (or 414 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 41.

The square root of 1286723840 is about 35870.9330795841. The cubic root of 1286723840 is about 1087.6649054549.

The spelling of 1286723840 in words is "one billion, two hundred eighty-six million, seven hundred twenty-three thousand, eight hundred forty".