78487961 has 4 divisors (see below), whose sum is σ = 78756132. Its totient is φ = 78219792.

The previous prime is 78487933. The next prime is 78487967. The reversal of 78487961 is 16978487.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 39187600 + 39300361 = 6260^2 + 6269^2 .

It is a cyclic number.

It is not a de Polignac number, because 78487961 - 2¹⁸ = 78225817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78487967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 133646 + ... + 134231.

It is an arithmetic number, because the mean of its divisors is an integer number (19689033).

Almost surely, 2^78487961 is an apocalyptic number.

It is an amenable number.

78487961 is a deficient number, since it is larger than the sum of its proper divisors (268171).

78487961 is a wasteful number, since it uses less digits than its factorization.

78487961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268170.

The product of its digits is 677376, while the sum is 50.

The square root of 78487961 is about 8859.3431472091. The cubic root of 78487961 is about 428.1549956145.

The spelling of 78487961 in words is "seventy-eight million, four hundred eighty-seven thousand, nine hundred sixty-one".