78264221 has 6 divisors (see below), whose sum is σ = 91042110. Its totient is φ = 67083576.

The previous prime is 78264217. The next prime is 78264227. The reversal of 78264221 is 12246287.

It can be written as a sum of positive squares in only one way, i.e., 40576900 + 37687321 = 6370^2 + 6139^2 .

It is not a de Polignac number, because 78264221 - 2² = 78264217 is a prime.

It is a super-2 number, since 2×78264221² = 12250576577473682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78264227) 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, 798566 + ... + 798663.

It is an arithmetic number, because the mean of its divisors is an integer number (15173685).

Almost surely, 2^78264221 is an apocalyptic number.

It is an amenable number.

78264221 is a deficient number, since it is larger than the sum of its proper divisors (12777889).

78264221 is a wasteful number, since it uses less digits than its factorization.

78264221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1597243 (or 1597236 counting only the distinct ones).

The product of its digits is 10752, while the sum is 32.

The square root of 78264221 is about 8846.7067884044. The cubic root of 78264221 is about 427.7477715102.

The spelling of 78264221 in words is "seventy-eight million, two hundred sixty-four thousand, two hundred twenty-one".