1261295040 has 112 divisors (see below), whose sum is σ = 4055546880. Its totient is φ = 332067840.

The previous prime is 1261295023. The next prime is 1261295041. The reversal of 1261295040 is 405921621.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1261294989 and 1261295007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261295041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67525 + ... + 84155.

It is an arithmetic number, because the mean of its divisors is an integer number (36210240).

Almost surely, 2^1261295040 is an apocalyptic number.

1261295040 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 1261295040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2027773440).

1261295040 is an abundant number, since it is smaller than the sum of its proper divisors (2794251840).

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

1261295040 is a wasteful number, since it uses less digits than its factorization.

1261295040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16730 (or 16720 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 1261295040 is about 35514.7158231627. The cubic root of 1261295040 is about 1080.4522111751.

The spelling of 1261295040 in words is "one billion, two hundred sixty-one million, two hundred ninety-five thousand, forty".