1285240720 has 40 divisors (see below), whose sum is σ = 3037182840. Its totient is φ = 505666560.

The previous prime is 1285240673. The next prime is 1285240721. The reversal of 1285240720 is 270425821.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 146313216 + 1138927504 = 12096^2 + 33748^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×1285240720² = 3303687416692236800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1285240721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126805 + ... + 136564.

It is an arithmetic number, because the mean of its divisors is an integer number (75929571).

Almost surely, 2^1285240720 is an apocalyptic number.

1285240720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1285240720 is an abundant number, since it is smaller than the sum of its proper divisors (1751942120).

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

1285240720 is a wasteful number, since it uses less digits than its factorization.

1285240720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263443 (or 263437 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 31.

The square root of 1285240720 is about 35850.2541134648. The cubic root of 1285240720 is about 1087.2468520735.

The spelling of 1285240720 in words is "one billion, two hundred eighty-five million, two hundred forty thousand, seven hundred twenty".