78640445 has 8 divisors (see below), whose sum is σ = 101627736. Its totient is φ = 58072896.

The previous prime is 78640439. The next prime is 78640481. The reversal of 78640445 is 54404687.

It can be written as a sum of positive squares in 4 ways, for example, as 4439449 + 74200996 = 2107^2 + 8614^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 78640445 - 2⁸ = 78640189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78640399 and 78640408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 604862 + ... + 604991.

It is an arithmetic number, because the mean of its divisors is an integer number (12703467).

Almost surely, 2^78640445 is an apocalyptic number.

It is an amenable number.

78640445 is a deficient number, since it is larger than the sum of its proper divisors (22987291).

78640445 is a wasteful number, since it uses less digits than its factorization.

78640445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1209871.

The product of its (nonzero) digits is 107520, while the sum is 38.

The square root of 78640445 is about 8867.9448013618. The cubic root of 78640445 is about 428.4320850434.

The spelling of 78640445 in words is "seventy-eight million, six hundred forty thousand, four hundred forty-five".