99621 has 6 divisors (see below), whose sum is σ = 143910. Its totient is φ = 66408.

The previous prime is 99611. The next prime is 99623. The reversal of 99621 is 12699.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 65025 + 34596 = 255^2 + 186^2 .

It is not a de Polignac number, because 99621 - 2⁹ = 99109 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 (99623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5526 + ... + 5543.

It is an arithmetic number, because the mean of its divisors is an integer number (23985).

2⁹⁹⁶²¹ is an apocalyptic number.

It is an amenable number.

99621 is a deficient number, since it is larger than the sum of its proper divisors (44289).

99621 is a wasteful number, since it uses less digits than its factorization.

99621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11075 (or 11072 counting only the distinct ones).

The product of its digits is 972, while the sum is 27.

The square root of 99621 is about 315.6279455308. The cubic root of 99621 is about 46.3571753605.

The spelling of 99621 in words is "ninety-nine thousand, six hundred twenty-one".