9966021 has 16 divisors (see below), whose sum is σ = 14617344. Its totient is φ = 6001344.

The previous prime is 9966007. The next prime is 9966023. The reversal of 9966021 is 1206699.

It is a happy number.

It is not a de Polignac number, because 9966021 - 2⁶ = 9965957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9966023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 886 + ... + 4551.

It is an arithmetic number, because the mean of its divisors is an integer number (913584).

Almost surely, 2^9966021 is an apocalyptic number.

It is an amenable number.

9966021 is a deficient number, since it is larger than the sum of its proper divisors (4651323).

9966021 is a wasteful number, since it uses less digits than its factorization.

9966021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5500.

The product of its (nonzero) digits is 5832, while the sum is 33.

The square root of 9966021 is about 3156.9005369191. The cubic root of 9966021 is about 215.1991736424.

It can be divided in two parts, 99660 and 21, that added together give a triangular number (99681 = T₄₄₆).

The spelling of 9966021 in words is "nine million, nine hundred sixty-six thousand, twenty-one".