9991969 has 4 divisors (see below), whose sum is σ = 10760596. Its totient is φ = 9223344.

The previous prime is 9991963. The next prime is 9991973. The reversal of 9991969 is 9691999.

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 3294225 + 6697744 = 1815^2 + 2588^2 .

It is not a de Polignac number, because 9991969 - 2¹¹ = 9989921 is a prime.

It is a super-2 number, since 2×9991969² = 199678888993922, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (9991963) 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, 384294 + ... + 384319.

It is an arithmetic number, because the mean of its divisors is an integer number (2690149).

Almost surely, 2^9991969 is an apocalyptic number.

It is an amenable number.

9991969 is a deficient number, since it is larger than the sum of its proper divisors (768627).

9991969 is a wasteful number, since it uses less digits than its factorization.

9991969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 768626.

The product of its digits is 354294, while the sum is 52.

The square root of 9991969 is about 3161.0075925249. The cubic root of 9991969 is about 215.3857793403.

The spelling of 9991969 in words is "nine million, nine hundred ninety-one thousand, nine hundred sixty-nine".