9780021 has 24 divisors (see below), whose sum is σ = 14798784. Its totient is φ = 6454080.

The previous prime is 9780013. The next prime is 9780031. The reversal of 9780021 is 1200879.

It is not a de Polignac number, because 9780021 - 2³ = 9780013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9780011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 40461 + ... + 40701.

It is an arithmetic number, because the mean of its divisors is an integer number (616616).

Almost surely, 2^9780021 is an apocalyptic number.

It is an amenable number.

9780021 is a deficient number, since it is larger than the sum of its proper divisors (5018763).

9780021 is a wasteful number, since it uses less digits than its factorization.

9780021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423 (or 411 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 9780021 is about 3127.3025117503. The cubic root of 9780021 is about 213.8519735045.

The spelling of 9780021 in words is "nine million, seven hundred eighty thousand, twenty-one".