77399031808 has 256 divisors, whose sum is σ = 195686461440. Its totient is φ = 29827792896.

The previous prime is 77399031793. The next prime is 77399031821. The reversal of 77399031808 is 80813099377.

It is a tau number, because it is divible by the number of its divisors (256).

It is a super-2 number, since 2×77399031808² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89685585 + ... + 89686447.

It is an arithmetic number, because the mean of its divisors is an integer number (764400240).

Almost surely, 2^77399031808 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 77399031808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97843230720).

77399031808 is an abundant number, since it is smaller than the sum of its proper divisors (118287429632).

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

77399031808 is an equidigital number, since it uses as much as digits as its factorization.

77399031808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 940 (or 912 counting only the distinct ones).

The product of its (nonzero) digits is 2286144, while the sum is 55.

The spelling of 77399031808 in words is "seventy-seven billion, three hundred ninety-nine million, thirty-one thousand, eight hundred eight".