991645522595 has 128 divisors (see below), whose sum is σ = 1523701186560. Its totient is φ = 602684375040.

The previous prime is 991645522591. The next prime is 991645522603. The reversal of 991645522595 is 595225546199.

It is a happy number.

It is a Cunningham number, because it is equal to 995814²-1.

It is not a de Polignac number, because 991645522595 - 2² = 991645522591 is a prime.

It is not an unprimeable number, because it can be changed into a prime (991645522591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1379200646 + ... + 1379201364.

It is an arithmetic number, because the mean of its divisors is an integer number (11903915520).

Almost surely, 2^991645522595 is an apocalyptic number.

991645522595 is a deficient number, since it is larger than the sum of its proper divisors (532055663965).

991645522595 is a wasteful number, since it uses less digits than its factorization.

With its successor (991645522596) it forms an eRAP, since the sums of their prime factors are consecutive (1405 and 1406).

991645522595 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1405.

The product of its digits is 43740000, while the sum is 62.

The spelling of 991645522595 in words is "nine hundred ninety-one billion, six hundred forty-five million, five hundred twenty-two thousand, five hundred ninety-five".