78561209880 has 672 divisors, whose sum is σ = 296833442400. Its totient is φ = 18637019136.

The previous prime is 78561209869. The next prime is 78561209933. The reversal of 78561209880 is 8890216587.

78561209880 is a `hidden beast` number, since 78 + 561 + 2 + 0 + 9 + 8 + 8 + 0 = 666.

It is a super-2 number, since 2×78561209880² (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 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 167 ways as a sum of consecutive naturals, for example, 178954701 + ... + 178955139.

Almost surely, 2^78561209880 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 78561209880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148416721200).

78561209880 is an abundant number, since it is smaller than the sum of its proper divisors (218272232520).

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

78561209880 is a wasteful number, since it uses less digits than its factorization.

78561209880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523 (or 485 counting only the distinct ones).

The product of its (nonzero) digits is 1935360, while the sum is 54.

The spelling of 78561209880 in words is "seventy-eight billion, five hundred sixty-one million, two hundred nine thousand, eight hundred eighty".