1291394326221 has 24 divisors (see below), whose sum is σ = 1943185221120. Its totient is φ = 825513962400.

The previous prime is 1291394326207. The next prime is 1291394326237. The reversal of 1291394326221 is 1226234931921.

1291394326221 is a `hidden beast` number, since 1 + 2 + 9 + 1 + 394 + 32 + 6 + 221 = 666.

It is not a de Polignac number, because 1291394326221 - 2¹⁴ = 1291394309837 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291394326291) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21201945 + ... + 21262766.

It is an arithmetic number, because the mean of its divisors is an integer number (80966050880).

Almost surely, 2^{1291394326221} is an apocalyptic number.

It is an amenable number.

1291394326221 is a deficient number, since it is larger than the sum of its proper divisors (651790894899).

1291394326221 is a wasteful number, since it uses less digits than its factorization.

1291394326221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42464857 (or 42464854 counting only the distinct ones).

The product of its digits is 279936, while the sum is 45.

The spelling of 1291394326221 in words is "one trillion, two hundred ninety-one billion, three hundred ninety-four million, three hundred twenty-six thousand, two hundred twenty-one".