99693821 has 4 divisors (see below), whose sum is σ = 100064700. Its totient is φ = 99322944.

The previous prime is 99693773. The next prime is 99693829. The reversal of 99693821 is 12839699.

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 45832900 + 53860921 = 6770^2 + 7339^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99693821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99693829) 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, 185036 + ... + 185573.

It is an arithmetic number, because the mean of its divisors is an integer number (25016175).

Almost surely, 2^99693821 is an apocalyptic number.

It is an amenable number.

99693821 is a deficient number, since it is larger than the sum of its proper divisors (370879).

99693821 is a wasteful number, since it uses less digits than its factorization.

99693821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370878.

The product of its digits is 209952, while the sum is 47.

The square root of 99693821 is about 9984.6793138288. The cubic root of 99693821 is about 463.6846800520.

The spelling of 99693821 in words is "ninety-nine million, six hundred ninety-three thousand, eight hundred twenty-one".