78234561 has 12 divisors (see below), whose sum is σ = 119653092. Its totient is φ = 49088256.

The previous prime is 78234529. The next prime is 78234581. The reversal of 78234561 is 16543287.

78234561 is a `hidden beast` number, since 78 + 23 + 4 + 561 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 59907600 + 18326961 = 7740^2 + 4281^2 .

It is not a de Polignac number, because 78234561 - 2⁵ = 78234529 is a prime.

It is a super-2 number, since 2×78234561² = 12241293069725442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78234581) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 255516 + ... + 255821.

It is an arithmetic number, because the mean of its divisors is an integer number (9971091).

Almost surely, 2^78234561 is an apocalyptic number.

It is an amenable number.

78234561 is a deficient number, since it is larger than the sum of its proper divisors (41418531).

78234561 is a wasteful number, since it uses less digits than its factorization.

78234561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511360 (or 511357 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 78234561 is about 8845.0302995524. The cubic root of 78234561 is about 427.6937297793.

The spelling of 78234561 in words is "seventy-eight million, two hundred thirty-four thousand, five hundred sixty-one".