78965221 has 16 divisors (see below), whose sum is σ = 86168880. Its totient is φ = 72069120.

The previous prime is 78965209. The next prime is 78965239. The reversal of 78965221 is 12256987.

It can be written as a sum of positive squares in 8 ways, for example, as 376996 + 78588225 = 614^2 + 8865^2 .

It is not a de Polignac number, because 78965221 - 2⁵ = 78965189 is a prime.

It is a super-3 number, since 3×78965221³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78965261) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 192865 + ... + 193273.

It is an arithmetic number, because the mean of its divisors is an integer number (5385555).

Almost surely, 2^78965221 is an apocalyptic number.

It is an amenable number.

78965221 is a deficient number, since it is larger than the sum of its proper divisors (7203659).

78965221 is a wasteful number, since it uses less digits than its factorization.

78965221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 744.

The product of its digits is 60480, while the sum is 40.

The square root of 78965221 is about 8886.2377303333. The cubic root of 78965221 is about 429.0210667348.

The spelling of 78965221 in words is "seventy-eight million, nine hundred sixty-five thousand, two hundred twenty-one".