9966421 has 4 divisors (see below), whose sum is σ = 9978592. Its totient is φ = 9954252.

The previous prime is 9966419. The next prime is 9966433. The reversal of 9966421 is 1246699.

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.

It is a cyclic number.

It is not a de Polignac number, because 9966421 - 2¹ = 9966419 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 (9966721) 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, 4761 + ... + 6526.

It is an arithmetic number, because the mean of its divisors is an integer number (2494648).

Almost surely, 2^9966421 is an apocalyptic number.

It is an amenable number.

9966421 is a deficient number, since it is larger than the sum of its proper divisors (12171).

9966421 is a wasteful number, since it uses less digits than its factorization.

9966421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12170.

The product of its digits is 23328, while the sum is 37.

The square root of 9966421 is about 3156.9638895622. The cubic root of 9966421 is about 215.2020527091.

The spelling of 9966421 in words is "nine million, nine hundred sixty-six thousand, four hundred twenty-one".