1221000997 has 2 divisors, whose sum is σ = 1221000998. Its totient is φ = 1221000996.

The previous prime is 1221000973. The next prime is 1221001051. The reversal of 1221000997 is 7990001221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 790396996 + 430604001 = 28114^2 + 20751^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221000997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221000947) 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, 610500498 + 610500499.

It is an arithmetic number, because the mean of its divisors is an integer number (610500499).

Almost surely, 2^1221000997 is an apocalyptic number.

It is an amenable number.

1221000997 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221000997 is an equidigital number, since it uses as much as digits as its factorization.

1221000997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2268, while the sum is 31.

The square root of 1221000997 is about 34942.8246854773. The cubic root of 1221000997 is about 1068.8218893448.

The spelling of 1221000997 in words is "one billion, two hundred twenty-one million, nine hundred ninety-seven", and thus it is an aban number.