77936281920 has 504 divisors, whose sum is σ = 318190863744. Its totient is φ = 17810648064.

The previous prime is 77936281909. The next prime is 77936281981. The reversal of 77936281920 is 2918263977.

77936281920 is a `hidden beast` number, since 7 + 7 + 9 + 3 + 628 + 1 + 9 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (504).

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 polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 14693989 + ... + 14699291.

Almost surely, 2^77936281920 is an apocalyptic number.

77936281920 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 77936281920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159095431872).

77936281920 is an abundant number, since it is smaller than the sum of its proper divisors (240254581824).

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

77936281920 is an frugal number, since it uses more digits than its factorization.

77936281920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5351 (or 5320 counting only the distinct ones).

The product of its (nonzero) digits is 2286144, while the sum is 54.

The spelling of 77936281920 in words is "seventy-seven billion, nine hundred thirty-six million, two hundred eighty-one thousand, nine hundred twenty".