1001221999 has 2 divisors, whose sum is σ = 1001222000. Its totient is φ = 1001221998.

The previous prime is 1001221981. The next prime is 1001222017. The reversal of 1001221999 is 9991221001.

It is a balanced prime because it is at equal distance from previous prime (1001221981) and next prime (1001222017).

It is a cyclic number.

It is not a de Polignac number, because 1001221999 - 2²⁹ = 464351087 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001221909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500610999 + 500611000.

It is an arithmetic number, because the mean of its divisors is an integer number (500611000).

Almost surely, 2^1001221999 is an apocalyptic number.

1001221999 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001221999 is an equidigital number, since it uses as much as digits as its factorization.

1001221999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916, while the sum is 34.

The square root of 1001221999 is about 31642.0922032662. The cubic root of 1001221999 is about 1000.4071671924.

The spelling of 1001221999 in words is "one billion, one million, two hundred twenty-one thousand, nine hundred ninety-nine".