1261319040 has 320 divisors, whose sum is σ = 4665276000. Its totient is φ = 324366336.

The previous prime is 1261319027. The next prime is 1261319071. The reversal of 1261319040 is 409131621.

1261319040 is a `hidden beast` number, since 1 + 2 + 613 + 1 + 9 + 0 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 1261318995 and 1261319013.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1502941 + ... + 1503779.

Almost surely, 2^1261319040 is an apocalyptic number.

1261319040 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 1261319040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2332638000).

1261319040 is an abundant number, since it is smaller than the sum of its proper divisors (3403956960).

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

1261319040 is an equidigital number, since it uses as much as digits as its factorization.

1261319040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 899 (or 878 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 1261319040 is about 35515.0537096595. The cubic root of 1261319040 is about 1080.4590641021.

The spelling of 1261319040 in words is "one billion, two hundred sixty-one million, three hundred nineteen thousand, forty".