78132321 has 6 divisors (see below), whose sum is σ = 112857810. Its totient is φ = 52088208.

The previous prime is 78132319. The next prime is 78132337. The reversal of 78132321 is 12323187.

It can be written as a sum of positive squares in only one way, i.e., 50253921 + 27878400 = 7089^2 + 5280^2 .

It is not a de Polignac number, because 78132321 - 2¹ = 78132319 is a prime.

It is a super-2 number, since 2×78132321² = 12209319169694082, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (78132361) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4340676 + ... + 4340693.

It is an arithmetic number, because the mean of its divisors is an integer number (18809635).

Almost surely, 2^78132321 is an apocalyptic number.

It is an amenable number.

78132321 is a deficient number, since it is larger than the sum of its proper divisors (34725489).

78132321 is a wasteful number, since it uses less digits than its factorization.

78132321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8681375 (or 8681372 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 78132321 is about 8839.2488934298. The cubic root of 78132321 is about 427.5073395683.

The spelling of 78132321 in words is "seventy-eight million, one hundred thirty-two thousand, three hundred twenty-one".