999727694221 has 2 divisors, whose sum is σ = 999727694222. Its totient is φ = 999727694220.

The previous prime is 999727694219. The next prime is 999727694237. The reversal of 999727694221 is 122496727999.

999727694221 = 707010² + 707011².

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 499864554121 + 499863140100 = 707011^2 + 707010^2 .

It is a cyclic number.

It is not a de Polignac number, because 999727694221 - 2¹ = 999727694219 is a prime.

Together with 999727694219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999727694261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499863847110 + 499863847111.

It is an arithmetic number, because the mean of its divisors is an integer number (499863847111).

Almost surely, 2^999727694221 is an apocalyptic number.

999727694221 is the 707011-st centered square number.

It is an amenable number.

999727694221 is a deficient number, since it is larger than the sum of its proper divisors (1).

999727694221 is an equidigital number, since it uses as much as digits as its factorization.

999727694221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 61725888, while the sum is 67.

The spelling of 999727694221 in words is "nine hundred ninety-nine billion, seven hundred twenty-seven million, six hundred ninety-four thousand, two hundred twenty-one".