76991905 has 4 divisors (see below), whose sum is σ = 92390292. Its totient is φ = 61593520.

The previous prime is 76991869. The next prime is 76991921. The reversal of 76991905 is 50919967.

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 38638656 + 38353249 = 6216^2 + 6193^2 .

It is not a de Polignac number, because 76991905 - 2⁹ = 76991393 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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, 7699186 + ... + 7699195.

It is an arithmetic number, because the mean of its divisors is an integer number (23097573).

Almost surely, 2^76991905 is an apocalyptic number.

It is an amenable number.

76991905 is a deficient number, since it is larger than the sum of its proper divisors (15398387).

76991905 is a wasteful number, since it uses less digits than its factorization.

76991905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15398386.

The product of its (nonzero) digits is 153090, while the sum is 46.

The square root of 76991905 is about 8774.5031198353. The cubic root of 76991905 is about 425.4171774490.

It can be divided in two parts, 7699 and 1905, that added together give a square (9604 = 98²).

The spelling of 76991905 in words is "seventy-six million, nine hundred ninety-one thousand, nine hundred five".