1221505451291 has 2 divisors, whose sum is σ = 1221505451292. Its totient is φ = 1221505451290.

The previous prime is 1221505451281. The next prime is 1221505451303. The reversal of 1221505451291 is 1921545051221.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221505451291 - 2¹⁴ = 1221505434907 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221505451281) 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 as a sum of consecutive naturals, namely, 610752725645 + 610752725646.

It is an arithmetic number, because the mean of its divisors is an integer number (610752725646).

Almost surely, 2^{1221505451291} is an apocalyptic number.

1221505451291 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221505451291 is an equidigital number, since it uses as much as digits as its factorization.

1221505451291 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36000, while the sum is 38.

The spelling of 1221505451291 in words is "one trillion, two hundred twenty-one billion, five hundred five million, four hundred fifty-one thousand, two hundred ninety-one".