78300821521 has 8 divisors (see below), whose sum is σ = 84412457640. Its totient is φ = 72201827712.

The previous prime is 78300821519. The next prime is 78300821527. The reversal of 78300821521 is 12512800387.

It can be written as a sum of positive squares in 4 ways, for example, as 535691025 + 77765130496 = 23145^2 + 278864^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78300821521 - 2¹ = 78300821519 is a prime.

It is a super-2 number, since 2×78300821521² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78300821527) 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 7 ways as a sum of consecutive naturals, for example, 3147706 + ... + 3172483.

It is an arithmetic number, because the mean of its divisors is an integer number (10551557205).

Almost surely, 2^78300821521 is an apocalyptic number.

It is an amenable number.

78300821521 is a deficient number, since it is larger than the sum of its proper divisors (6111636119).

78300821521 is a wasteful number, since it uses less digits than its factorization.

78300821521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6321155.

The product of its (nonzero) digits is 26880, while the sum is 37.

The spelling of 78300821521 in words is "seventy-eight billion, three hundred million, eight hundred twenty-one thousand, five hundred twenty-one".