77857884820 has 24 divisors (see below), whose sum is σ = 163508540328. Its totient is φ = 31141824000.

The previous prime is 77857884799. The next prime is 77857884823. The reversal of 77857884820 is 2848875877.

It can be written as a sum of positive squares in 4 ways, for example, as 35765617924 + 42092266896 = 189118^2 + 205164^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77857884823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 495000 + ... + 633040.

It is an arithmetic number, because the mean of its divisors is an integer number (6812855847).

Almost surely, 2^77857884820 is an apocalyptic number.

It is an amenable number.

77857884820 is an abundant number, since it is smaller than the sum of its proper divisors (85650655508).

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

77857884820 is a wasteful number, since it uses less digits than its factorization.

77857884820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166251 (or 166249 counting only the distinct ones).

The product of its (nonzero) digits is 56197120, while the sum is 64.

The spelling of 77857884820 in words is "seventy-seven billion, eight hundred fifty-seven million, eight hundred eighty-four thousand, eight hundred twenty".