77813809920 has 1728 divisors, whose sum is σ = 367825812480. Its totient is φ = 15318097920.

The previous prime is 77813809907. The next prime is 77813809943. The reversal of 77813809920 is 2990831877.

It is a tau number, because it is divible by the number of its divisors (1728).

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 191 ways as a sum of consecutive naturals, for example, 4095463671 + ... + 4095463689.

It is an arithmetic number, because the mean of its divisors is an integer number (212862160).

Almost surely, 2^77813809920 is an apocalyptic number.

77813809920 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 77813809920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (183912906240).

77813809920 is an abundant number, since it is smaller than the sum of its proper divisors (290012002560).

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

77813809920 is an equidigital number, since it uses as much as digits as its factorization.

77813809920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 1524096, while the sum is 54.

The spelling of 77813809920 in words is "seventy-seven billion, eight hundred thirteen million, eight hundred nine thousand, nine hundred twenty".