9987421 has 4 divisors (see below), whose sum is σ = 10003644. Its totient is φ = 9971200.

The previous prime is 9987413. The next prime is 9987427. The reversal of 9987421 is 1247899.

9987421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 6320196 + 3667225 = 2514^2 + 1915^2 .

It is a cyclic number.

It is not a de Polignac number, because 9987421 - 2³ = 9987413 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 (9987427) 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, 7150 + ... + 8431.

It is an arithmetic number, because the mean of its divisors is an integer number (2500911).

Almost surely, 2^9987421 is an apocalyptic number.

It is an amenable number.

9987421 is a deficient number, since it is larger than the sum of its proper divisors (16223).

9987421 is a wasteful number, since it uses less digits than its factorization.

9987421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16222.

The product of its digits is 36288, while the sum is 40.

The square root of 9987421 is about 3160.2881197764. The cubic root of 9987421 is about 215.3530956525.

The spelling of 9987421 in words is "nine million, nine hundred eighty-seven thousand, four hundred twenty-one".