778791506640 has 80 divisors (see below), whose sum is σ = 2759147058048. Its totient is φ = 178009486848.

The previous prime is 778791506629. The next prime is 778791506653. The reversal of 778791506640 is 46605197877.

778791506640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a hoax number, since the sum of its digits (60) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 231781507 + ... + 231784866.

Almost surely, 2^778791506640 is an apocalyptic number.

778791506640 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

778791506640 is an abundant number, since it is smaller than the sum of its proper divisors (1980355551408).

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

778791506640 is a wasteful number, since it uses less digits than its factorization.

778791506640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 463566396 (or 463566390 counting only the distinct ones).

The product of its (nonzero) digits is 17781120, while the sum is 60.

The spelling of 778791506640 in words is "seven hundred seventy-eight billion, seven hundred ninety-one million, five hundred six thousand, six hundred forty".