9865421 has 4 divisors (see below), whose sum is σ = 10132092. Its totient is φ = 9598752.

The previous prime is 9865417. The next prime is 9865433. The reversal of 9865421 is 1245689.

9865421 = 328² + 329² + ... + 401².

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 9030025 + 835396 = 3005^2 + 914^2 .

It is a cyclic number.

It is not a de Polignac number, because 9865421 - 2² = 9865417 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9865411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is an upside-down number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 133280 + ... + 133353.

It is an arithmetic number, because the mean of its divisors is an integer number (2533023).

Almost surely, 2^9865421 is an apocalyptic number.

It is an amenable number.

9865421 is a deficient number, since it is larger than the sum of its proper divisors (266671).

9865421 is a wasteful number, since it uses less digits than its factorization.

9865421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266670.

The product of its digits is 17280, while the sum is 35.

The square root of 9865421 is about 3140.9267740589. The cubic root of 9865421 is about 214.4726285115.

The spelling of 9865421 in words is "nine million, eight hundred sixty-five thousand, four hundred twenty-one".