221001001993 has 2 divisors, whose sum is σ = 221001001994. Its totient is φ = 221001001992.

The previous prime is 221001001987. The next prime is 221001002009. The reversal of 221001001993 is 399100100122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 113550128784 + 107450873209 = 336972^2 + 327797^2 .

It is a cyclic number.

It is not a de Polignac number, because 221001001993 - 2¹⁷ = 221000870921 is a prime.

It is not a weakly prime, because it can be changed into another prime (221001001943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110500500996 + 110500500997.

It is an arithmetic number, because the mean of its divisors is an integer number (110500500997).

Almost surely, 2^221001001993 is an apocalyptic number.

It is an amenable number.

221001001993 is a deficient number, since it is larger than the sum of its proper divisors (1).

221001001993 is an equidigital number, since it uses as much as digits as its factorization.

221001001993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 28.

The spelling of 221001001993 in words is "two hundred twenty-one billion, one million, one thousand, nine hundred ninety-three".