1021213101991 has 2 divisors, whose sum is σ = 1021213101992. Its totient is φ = 1021213101990.

The previous prime is 1021213101983. The next prime is 1021213102009. The reversal of 1021213101991 is 1991013121201.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1021213101991 - 2³ = 1021213101983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021213101971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510606550995 + 510606550996.

It is an arithmetic number, because the mean of its divisors is an integer number (510606550996).

Almost surely, 2^{1021213101991} is an apocalyptic number.

1021213101991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021213101991 is an equidigital number, since it uses as much as digits as its factorization.

1021213101991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 31.

The spelling of 1021213101991 in words is "one trillion, twenty-one billion, two hundred thirteen million, one hundred one thousand, nine hundred ninety-one".