99173821 has 2 divisors, whose sum is σ = 99173822. Its totient is φ = 99173820.

The previous prime is 99173797. The next prime is 99173831. The reversal of 99173821 is 12837199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54096025 + 45077796 = 7355^2 + 6714^2 .

It is a cyclic number.

It is not a de Polignac number, because 99173821 - 2⁷ = 99173693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99173831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49586910 + 49586911.

It is an arithmetic number, because the mean of its divisors is an integer number (49586911).

Almost surely, 2^99173821 is an apocalyptic number.

It is an amenable number.

99173821 is a deficient number, since it is larger than the sum of its proper divisors (1).

99173821 is an equidigital number, since it uses as much as digits as its factorization.

99173821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 40.

The square root of 99173821 is about 9958.6053742479. The cubic root of 99173821 is about 462.8770857991.

The spelling of 99173821 in words is "ninety-nine million, one hundred seventy-three thousand, eight hundred twenty-one".