991063553 has 4 divisors (see below), whose sum is σ = 991379460. Its totient is φ = 990747648.

The previous prime is 991063547. The next prime is 991063559. The reversal of 991063553 is 355360199.

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

It is an interprime number because it is at equal distance from previous prime (991063547) and next prime (991063559).

It can be written as a sum of positive squares in 2 ways, for example, as 933485809 + 57577744 = 30553^2 + 7588^2 .

It is a cyclic number.

It is not a de Polignac number, because 991063553 - 2¹² = 991059457 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 991063553.

It is not an unprimeable number, because it can be changed into a prime (991063559) 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, 153200 + ... + 159537.

It is an arithmetic number, because the mean of its divisors is an integer number (247844865).

Almost surely, 2^991063553 is an apocalyptic number.

It is an amenable number.

991063553 is a deficient number, since it is larger than the sum of its proper divisors (315907).

991063553 is a wasteful number, since it uses less digits than its factorization.

991063553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315906.

The product of its (nonzero) digits is 109350, while the sum is 41.

The square root of 991063553 is about 31481.1618750007. The cubic root of 991063553 is about 997.0122666730.

The spelling of 991063553 in words is "nine hundred ninety-one million, sixty-three thousand, five hundred fifty-three".