9942821 has 4 divisors (see below), whose sum is σ = 11363232. Its totient is φ = 8522412.

The previous prime is 9942797. The next prime is 9942883. The reversal of 9942821 is 1282499.

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 9942821 - 2²² = 5748517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9942421) 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, 710195 + ... + 710208.

It is an arithmetic number, because the mean of its divisors is an integer number (2840808).

Almost surely, 2^9942821 is an apocalyptic number.

It is an amenable number.

9942821 is a deficient number, since it is larger than the sum of its proper divisors (1420411).

9942821 is a wasteful number, since it uses less digits than its factorization.

9942821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1420410.

The product of its digits is 10368, while the sum is 35.

The square root of 9942821 is about 3153.2239057828. The cubic root of 9942821 is about 215.0320557936.

The spelling of 9942821 in words is "nine million, nine hundred forty-two thousand, eight hundred twenty-one".