1221133031851 has 2 divisors, whose sum is σ = 1221133031852. Its totient is φ = 1221133031850.

The previous prime is 1221133031779. The next prime is 1221133031971. The reversal of 1221133031851 is 1581303311221.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221133031851 - 2¹⁵ = 1221132999083 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221133031351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610566515925 + 610566515926.

It is an arithmetic number, because the mean of its divisors is an integer number (610566515926).

Almost surely, 2^{1221133031851} is an apocalyptic number.

1221133031851 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221133031851 is an equidigital number, since it uses as much as digits as its factorization.

1221133031851 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 31.

The spelling of 1221133031851 in words is "one trillion, two hundred twenty-one billion, one hundred thirty-three million, thirty-one thousand, eight hundred fifty-one".