9888665421 has 4 divisors (see below), whose sum is σ = 13184887232. Its totient is φ = 6592443612.

The previous prime is 9888665419. The next prime is 9888665447. The reversal of 9888665421 is 1245668889.

It is a happy number.

9888665421 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, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1245668889 = 3 ⋅415222963.

It is not a de Polignac number, because 9888665421 - 2¹ = 9888665419 is a prime.

It is a super-2 number, since 2×9888665421² (a number of 21 digits) contains 22 as substring.

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 (9888661421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1648110901 + ... + 1648110906.

It is an arithmetic number, because the mean of its divisors is an integer number (3296221808).

Almost surely, 2^9888665421 is an apocalyptic number.

It is an amenable number.

9888665421 is a deficient number, since it is larger than the sum of its proper divisors (3296221811).

9888665421 is a wasteful number, since it uses less digits than its factorization.

9888665421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3296221810.

The product of its digits is 6635520, while the sum is 57.

The square root of 9888665421 is about 99441.7689957294. The cubic root of 9888665421 is about 2146.4093968713.

The spelling of 9888665421 in words is "nine billion, eight hundred eighty-eight million, six hundred sixty-five thousand, four hundred twenty-one".