1921126286209 has 9 divisors (see below), whose sum is σ = 2080292353923. Its totient is φ = 1773330708552.

The previous prime is 1921126286171. The next prime is 1921126286213. The reversal of 1921126286209 is 9026826211291.

The square root of 1921126286209 is 1386047.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 284190279025 + 1636936007184 = 533095^2 + 1279428^2 .

It is not a de Polignac number, because 1921126286209 - 2⁹ = 1921126285697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1921126286279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 17965302 + ... + 18071920.

Almost surely, 2^{1921126286209} is an apocalyptic number.

1921126286209 is the 1386047-th square number.

1921126286209 is the 693024-th centered octagonal number.

It is an amenable number.

1921126286209 is a deficient number, since it is larger than the sum of its proper divisors (159166067714).

1921126286209 is an frugal number, since it uses more digits than its factorization.

1921126286209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213264 (or 106632 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 49.

Multiplying 1921126286209 by its sum of digits (49), we get a square (94135188024241 = 9702329²).

The spelling of 1921126286209 in words is "one trillion, nine hundred twenty-one billion, one hundred twenty-six million, two hundred eighty-six thousand, two hundred nine".