77747993856 has 432 divisors, whose sum is σ = 252655929344. Its totient is φ = 23702740992.

The previous prime is 77747993849. The next prime is 77747993861. The reversal of 77747993856 is 65839974777.

77747993856 is a `hidden beast` number, since 7 + 77 + 479 + 9 + 3 + 85 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (432).

It is a super-2 number, since 2×77747993856² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 102705030 + ... + 102705786.

Almost surely, 2^77747993856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77747993856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126327964672).

77747993856 is an abundant number, since it is smaller than the sum of its proper divisors (174907935488).

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

77747993856 is a wasteful number, since it uses less digits than its factorization.

77747993856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 928 (or 902 counting only the distinct ones).

The product of its digits is 560105280, while the sum is 72.

The spelling of 77747993856 in words is "seventy-seven billion, seven hundred forty-seven million, nine hundred ninety-three thousand, eight hundred fifty-six".