1309781340 has 240 divisors, whose sum is σ = 4943769600. Its totient is φ = 283575168.

The previous prime is 1309781309. The next prime is 1309781351. The reversal of 1309781340 is 431879031.

It is a happy number.

1309781340 is a `hidden beast` number, since 1 + 309 + 7 + 8 + 1 + 340 = 666.

It is a super-2 number, since 2×1309781340² = 3431054317224391200, 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 = 1309781295 and 1309781304.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 212421 + ... + 218499.

It is an arithmetic number, because the mean of its divisors is an integer number (20599040).

Almost surely, 2^1309781340 is an apocalyptic number.

1309781340 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 1309781340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2471884800).

1309781340 is an abundant number, since it is smaller than the sum of its proper divisors (3633988260).

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

1309781340 is a wasteful number, since it uses less digits than its factorization.

1309781340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6126 (or 6115 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 1309781340 is about 36190.9013427408. The cubic root of 1309781340 is about 1094.1232990159.

The spelling of 1309781340 in words is "one billion, three hundred nine million, seven hundred eighty-one thousand, three hundred forty".