1221001020971 has 2 divisors, whose sum is σ = 1221001020972. Its totient is φ = 1221001020970.

The previous prime is 1221001020937. The next prime is 1221001021013. The reversal of 1221001020971 is 1790201001221.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221001020971 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221001020971.

It is not a weakly prime, because it can be changed into another prime (1221001023971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610500510485 + 610500510486.

It is an arithmetic number, because the mean of its divisors is an integer number (610500510486).

Almost surely, 2^{1221001020971} is an apocalyptic number.

1221001020971 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221001020971 is an equidigital number, since it uses as much as digits as its factorization.

1221001020971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 504, while the sum is 26.

The spelling of 1221001020971 in words is "one trillion, two hundred twenty-one billion, one million, twenty thousand, nine hundred seventy-one".