9919521 has 6 divisors (see below), whose sum is σ = 14328210. Its totient is φ = 6613008.

The previous prime is 9919519. The next prime is 9919523. The reversal of 9919521 is 1259199.

It is an interprime number because it is at equal distance from previous prime (9919519) and next prime (9919523).

It can be written as a sum of positive squares in only one way, i.e., 8785296 + 1134225 = 2964^2 + 1065^2 .

It is not a de Polignac number, because 9919521 - 2¹ = 9919519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9919523) 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 5 ways as a sum of consecutive naturals, for example, 551076 + ... + 551093.

It is an arithmetic number, because the mean of its divisors is an integer number (2388035).

Almost surely, 2^9919521 is an apocalyptic number.

It is an amenable number.

9919521 is a deficient number, since it is larger than the sum of its proper divisors (4408689).

9919521 is a wasteful number, since it uses less digits than its factorization.

9919521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1102175 (or 1102172 counting only the distinct ones).

The product of its digits is 7290, while the sum is 36.

The square root of 9919521 is about 3149.5271073607. The cubic root of 9919521 is about 214.8639557587.

It can be divided in two parts, 9919 and 521, that added together give a triangular number (10440 = T₁₄₄).

The spelling of 9919521 in words is "nine million, nine hundred nineteen thousand, five hundred twenty-one".