78440405 has 8 divisors (see below), whose sum is σ = 94183992. Its totient is φ = 62715328.

The previous prime is 78440393. The next prime is 78440437. The reversal of 78440405 is 50404487.

It can be written as a sum of positive squares in 4 ways, for example, as 30096196 + 48344209 = 5486^2 + 6953^2 .

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 78440405 - 2²⁰ = 77391829 is a prime.

It is a Duffinian number.

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, 7679 + ... + 14691.

It is an arithmetic number, because the mean of its divisors is an integer number (11772999).

Almost surely, 2^78440405 is an apocalyptic number.

It is an amenable number.

78440405 is a deficient number, since it is larger than the sum of its proper divisors (15743587).

78440405 is a wasteful number, since it uses less digits than its factorization.

78440405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9255.

The product of its (nonzero) digits is 17920, while the sum is 32.

The square root of 78440405 is about 8856.6587943761. The cubic root of 78440405 is about 428.0685048439.

The spelling of 78440405 in words is "seventy-eight million, four hundred forty thousand, four hundred five".