999965521 has 4 divisors (see below), whose sum is σ = 1000031472. Its totient is φ = 999899572.

The previous prime is 999965507. The next prime is 999965537. The reversal of 999965521 is 125569999.

999965521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 999965521 - 2¹⁵ = 999932753 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (999965581) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2466 + ... + 44788.

It is an arithmetic number, because the mean of its divisors is an integer number (250007868).

Almost surely, 2^999965521 is an apocalyptic number.

It is an amenable number.

999965521 is a deficient number, since it is larger than the sum of its proper divisors (65951).

999965521 is a wasteful number, since it uses less digits than its factorization.

999965521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65950.

The product of its digits is 1968300, while the sum is 55.

The square root of 999965521 is about 31622.2314361273. The cubic root of 999965521 is about 999.9885068679.

The spelling of 999965521 in words is "nine hundred ninety-nine million, nine hundred sixty-five thousand, five hundred twenty-one".