1021201000991 has 2 divisors, whose sum is σ = 1021201000992. Its totient is φ = 1021201000990.

The previous prime is 1021201000973. The next prime is 1021201001011. The reversal of 1021201000991 is 1990001021201.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1021201000991 - 2¹⁸ = 1021200738847 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1021201000991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021201000291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510600500495 + 510600500496.

It is an arithmetic number, because the mean of its divisors is an integer number (510600500496).

Almost surely, 2^{1021201000991} is an apocalyptic number.

1021201000991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021201000991 is an equidigital number, since it uses as much as digits as its factorization.

1021201000991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 26.

The spelling of 1021201000991 in words is "one trillion, twenty-one billion, two hundred one million, nine hundred ninety-one", and thus it is an aban number.