9999621 has 12 divisors (see below), whose sum is σ = 15293772. Its totient is φ = 6274176.

The previous prime is 9999601. The next prime is 9999637. The reversal of 9999621 is 1269999.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 8767521 + 1232100 = 2961^2 + 1110^2 .

It is not a de Polignac number, because 9999621 - 2¹¹ = 9997573 is a prime.

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 (9999601) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32526 + ... + 32831.

It is an arithmetic number, because the mean of its divisors is an integer number (1274481).

Almost surely, 2^9999621 is an apocalyptic number.

It is an amenable number.

9999621 is a deficient number, since it is larger than the sum of its proper divisors (5294151).

9999621 is a wasteful number, since it uses less digits than its factorization.

9999621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65380 (or 65377 counting only the distinct ones).

The product of its digits is 78732, while the sum is 45.

The square root of 9999621 is about 3162.2177344389. The cubic root of 9999621 is about 215.4407471996.

The spelling of 9999621 in words is "nine million, nine hundred ninety-nine thousand, six hundred twenty-one".