991985528 has 8 divisors (see below), whose sum is σ = 1859972880. Its totient is φ = 495992760.

The previous prime is 991985441. The next prime is 991985537. The reversal of 991985528 is 825589199.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×991985528² = 1968070575522877568, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61999088 + ... + 61999103.

It is an arithmetic number, because the mean of its divisors is an integer number (232496610).

Almost surely, 2^991985528 is an apocalyptic number.

It is an amenable number.

991985528 is a deficient number, since it is larger than the sum of its proper divisors (867987352).

991985528 is a wasteful number, since it uses less digits than its factorization.

991985528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123998197 (or 123998193 counting only the distinct ones).

The product of its digits is 2332800, while the sum is 56.

The square root of 991985528 is about 31495.8017519796. The cubic root of 991985528 is about 997.3213405234.

The spelling of 991985528 in words is "nine hundred ninety-one million, nine hundred eighty-five thousand, five hundred twenty-eight".