21998088173 has 2 divisors, whose sum is σ = 21998088174. Its totient is φ = 21998088172.

The previous prime is 21998088169. The next prime is 21998088187. The reversal of 21998088173 is 37188089912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20454148324 + 1543939849 = 143018^2 + 39293^2 .

It is a cyclic number.

It is not a de Polignac number, because 21998088173 - 2² = 21998088169 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21998088473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10999044086 + 10999044087.

It is an arithmetic number, because the mean of its divisors is an integer number (10999044087).

Almost surely, 2^21998088173 is an apocalyptic number.

It is an amenable number.

21998088173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21998088173 is an equidigital number, since it uses as much as digits as its factorization.

21998088173 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1741824, while the sum is 56.

The spelling of 21998088173 in words is "twenty-one billion, nine hundred ninety-eight million, eighty-eight thousand, one hundred seventy-three".