77844138420 has 24 divisors (see below), whose sum is σ = 217963587744. Its totient is φ = 20758436896.

The previous prime is 77844138413. The next prime is 77844138431. The reversal of 77844138420 is 2483144877.

It is a self number, because there is not a number n which added to its sum of digits gives 77844138420.

It is a congruent number.

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, 648701094 + ... + 648701213.

It is an arithmetic number, because the mean of its divisors is an integer number (9081816156).

Almost surely, 2^77844138420 is an apocalyptic number.

It is an amenable number.

77844138420 is an abundant number, since it is smaller than the sum of its proper divisors (140119449324).

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

77844138420 is a wasteful number, since it uses less digits than its factorization.

77844138420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1297402319 (or 1297402317 counting only the distinct ones).

The product of its (nonzero) digits is 1204224, while the sum is 48.

The spelling of 77844138420 in words is "seventy-seven billion, eight hundred forty-four million, one hundred thirty-eight thousand, four hundred twenty".