221800993 has 2 divisors, whose sum is σ = 221800994. Its totient is φ = 221800992.

The previous prime is 221800987. The next prime is 221801059. The reversal of 221800993 is 399008122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 164147344 + 57653649 = 12812^2 + 7593^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221800993 is a prime.

It is not a weakly prime, because it can be changed into another prime (221800913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110900496 + 110900497.

It is an arithmetic number, because the mean of its divisors is an integer number (110900497).

Almost surely, 2^221800993 is an apocalyptic number.

It is an amenable number.

221800993 is a deficient number, since it is larger than the sum of its proper divisors (1).

221800993 is an equidigital number, since it uses as much as digits as its factorization.

221800993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 221800993 is about 14892.9846907865. The cubic root of 221800993 is about 605.3239100611.

The spelling of 221800993 in words is "two hundred twenty-one million, eight hundred thousand, nine hundred ninety-three".