77771839540 has 24 divisors (see below), whose sum is σ = 163399432392. Its totient is φ = 31093770240.

The previous prime is 77771839493. The next prime is 77771839549. The reversal of 77771839540 is 4593817777.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 6928564644 + 70843274896 = 83238^2 + 266164^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77771839549) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 892689 + ... + 975928.

It is an arithmetic number, because the mean of its divisors is an integer number (6808309683).

Almost surely, 2^77771839540 is an apocalyptic number.

It is an amenable number.

77771839540 is an abundant number, since it is smaller than the sum of its proper divisors (85627592852).

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

77771839540 is a wasteful number, since it uses less digits than its factorization.

77771839540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1870707 (or 1870705 counting only the distinct ones).

The product of its (nonzero) digits is 10372320, while the sum is 58.

The spelling of 77771839540 in words is "seventy-seven billion, seven hundred seventy-one million, eight hundred thirty-nine thousand, five hundred forty".