78978505 has 8 divisors (see below), whose sum is σ = 97086024. Its totient is φ = 61641600.

The previous prime is 78978503. The next prime is 78978509. The reversal of 78978505 is 50587987.

It can be written as a sum of positive squares in 4 ways, for example, as 4052169 + 74926336 = 2013^2 + 8656^2 .

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

It is not a de Polignac number, because 78978505 - 2¹ = 78978503 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78978503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 192426 + ... + 192835.

It is an arithmetic number, because the mean of its divisors is an integer number (12135753).

Almost surely, 2^78978505 is an apocalyptic number.

It is an amenable number.

78978505 is a deficient number, since it is larger than the sum of its proper divisors (18107519).

78978505 is a wasteful number, since it uses less digits than its factorization.

78978505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385307.

The product of its (nonzero) digits is 705600, while the sum is 49.

The square root of 78978505 is about 8886.9851468313. The cubic root of 78978505 is about 429.0451228793.

The spelling of 78978505 in words is "seventy-eight million, nine hundred seventy-eight thousand, five hundred five".