78213530 has 8 divisors (see below), whose sum is σ = 140784372. Its totient is φ = 31285408.

The previous prime is 78213511. The next prime is 78213533. The reversal of 78213530 is 3531287.

It can be written as a sum of positive squares in 2 ways, for example, as 75394489 + 2819041 = 8683^2 + 1679^2 .

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

It is a super-2 number, since 2×78213530² = 12234712550121800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78213493 and 78213502.

It is not an unprimeable number, because it can be changed into a prime (78213533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3910667 + ... + 3910686.

Almost surely, 2^78213530 is an apocalyptic number.

78213530 is a deficient number, since it is larger than the sum of its proper divisors (62570842).

78213530 is a wasteful number, since it uses less digits than its factorization.

78213530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7821360.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 78213530 is about 8843.8413599521. The cubic root of 78213530 is about 427.6554021620.

The spelling of 78213530 in words is "seventy-eight million, two hundred thirteen thousand, five hundred thirty".