78300821520 has 120 divisors (see below), whose sum is σ = 263217318936. Its totient is φ = 20859807744.

The previous prime is 78300821519. The next prime is 78300821527. The reversal of 78300821520 is 2512800387.

It can be written as a sum of positive squares in 4 ways, for example, as 26053833744 + 52246987776 = 161412^2 + 228576^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×78300821520² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (78300821527) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 691122 + ... + 796398.

Almost surely, 2^78300821520 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 78300821520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131608659468).

78300821520 is an abundant number, since it is smaller than the sum of its proper divisors (184916497416).

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

78300821520 is a wasteful number, since it uses less digits than its factorization.

78300821520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106329 (or 106320 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The spelling of 78300821520 in words is "seventy-eight billion, three hundred million, eight hundred twenty-one thousand, five hundred twenty".