999875221 has 2 divisors, whose sum is σ = 999875222. Its totient is φ = 999875220.

The previous prime is 999875207. The next prime is 999875231. The reversal of 999875221 is 122578999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 604422225 + 395452996 = 24585^2 + 19886^2 .

It is an emirp because it is prime and its reverse (122578999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999875221 - 2⁹ = 999874709 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999875231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499937610 + 499937611.

It is an arithmetic number, because the mean of its divisors is an integer number (499937611).

Almost surely, 2^999875221 is an apocalyptic number.

It is an amenable number.

999875221 is a deficient number, since it is larger than the sum of its proper divisors (1).

999875221 is an equidigital number, since it uses as much as digits as its factorization.

999875221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 816480, while the sum is 52.

The square root of 999875221 is about 31620.8036109141. The cubic root of 999875221 is about 999.9584052699.

The spelling of 999875221 in words is "nine hundred ninety-nine million, eight hundred seventy-five thousand, two hundred twenty-one".