1306778640 has 40 divisors (see below), whose sum is σ = 4051014528. Its totient is φ = 348474240.

The previous prime is 1306778633. The next prime is 1306778651. The reversal of 1306778640 is 468776031.

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

It is a junction number, because it is equal to n+sod(n) for n = 1306778592 and 1306778601.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2722216 + ... + 2722695.

Almost surely, 2^1306778640 is an apocalyptic number.

1306778640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1306778640 is an abundant number, since it is smaller than the sum of its proper divisors (2744235888).

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

1306778640 is a wasteful number, since it uses less digits than its factorization.

1306778640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5444927 (or 5444921 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 42.

The square root of 1306778640 is about 36149.3933559057. The cubic root of 1306778640 is about 1093.2865594042.

The spelling of 1306778640 in words is "one billion, three hundred six million, seven hundred seventy-eight thousand, six hundred forty".