77844049920 has 1872 divisors, whose sum is σ = 369102186720. Its totient is φ = 15458107392.

The previous prime is 77844049909. The next prime is 77844049931. The reversal of 77844049920 is 2994044877.

It is a happy number.

77844049920 is a `hidden beast` number, since 7 + 78 + 440 + 49 + 92 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (77844049909) and next prime (77844049931).

It is a tau number, because it is divible by the number of its divisors (1872).

It is a super-2 number, since 2×77844049920² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 4579061752 + ... + 4579061768.

Almost surely, 2^77844049920 is an apocalyptic number.

77844049920 is a gapful number since it is divisible by the number (70) 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 77844049920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (184551093360).

77844049920 is an abundant number, since it is smaller than the sum of its proper divisors (291258136800).

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

77844049920 is a wasteful number, since it uses less digits than its factorization.

77844049920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 4064256, while the sum is 54.

The spelling of 77844049920 in words is "seventy-seven billion, eight hundred forty-four million, forty-nine thousand, nine hundred twenty".