77838561900 has 648 divisors, whose sum is σ = 290453409792. Its totient is φ = 18033840000.

The previous prime is 77838561893. The next prime is 77838561901. The reversal of 77838561900 is 916583877.

77838561900 is a `hidden beast` number, since 7 + 78 + 3 + 8 + 561 + 9 + 0 + 0 = 666.

It is a super-2 number, since 2×77838561900² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (77838561901) by changing a digit.

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 215 ways as a sum of consecutive naturals, for example, 67626325 + ... + 67627475.

Almost surely, 2^77838561900 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 77838561900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145226704896).

77838561900 is an abundant number, since it is smaller than the sum of its proper divisors (212614847892).

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

77838561900 is a wasteful number, since it uses less digits than its factorization.

77838561900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1225 (or 1195 counting only the distinct ones).

The product of its (nonzero) digits is 2540160, while the sum is 54.

The spelling of 77838561900 in words is "seventy-seven billion, eight hundred thirty-eight million, five hundred sixty-one thousand, nine hundred".