77645993880 has 768 divisors, whose sum is σ = 304286976000. Its totient is φ = 15748992000.

The previous prime is 77645993863. The next prime is 77645993951. The reversal of 77645993880 is 8839954677.

It is a super-2 number, since 2×77645993880² (a number of 23 digits) contains 22 as substring.

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 191 ways as a sum of consecutive naturals, for example, 514211805 + ... + 514211955.

It is an arithmetic number, because the mean of its divisors is an integer number (396207000).

Almost surely, 2^77645993880 is an apocalyptic number.

77645993880 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 77645993880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (152143488000).

77645993880 is an abundant number, since it is smaller than the sum of its proper divisors (226640982120).

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

77645993880 is a wasteful number, since it uses less digits than its factorization.

77645993880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261 (or 212 counting only the distinct ones).

The product of its (nonzero) digits is 91445760, while the sum is 66.

The spelling of 77645993880 in words is "seventy-seven billion, six hundred forty-five million, nine hundred ninety-three thousand, eight hundred eighty".