76391561 has 4 divisors (see below), whose sum is σ = 76421124. Its totient is φ = 76362000.

The previous prime is 76391543. The next prime is 76391617. The reversal of 76391561 is 16519367.

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 21335161 + 55056400 = 4619^2 + 7420^2 .

It is a cyclic number.

It is not a de Polignac number, because 76391561 - 2¹⁴ = 76375177 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 8.

It is a zygodrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (76391531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10490 + ... + 16211.

It is an arithmetic number, because the mean of its divisors is an integer number (19105281).

Almost surely, 2^76391561 is an apocalyptic number.

It is an amenable number.

76391561 is a deficient number, since it is larger than the sum of its proper divisors (29563).

76391561 is a wasteful number, since it uses less digits than its factorization.

76391561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29562.

The product of its digits is 34020, while the sum is 38.

The square root of 76391561 is about 8740.2265988932. The cubic root of 76391561 is about 424.3085615122.

The spelling of 76391561 in words is "seventy-six million, three hundred ninety-one thousand, five hundred sixty-one".