221302993 has 2 divisors, whose sum is σ = 221302994. Its totient is φ = 221302992.

The previous prime is 221302979. The next prime is 221302997. The reversal of 221302993 is 399203122.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128527569 + 92775424 = 11337^2 + 9632^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221302993 is a prime.

It is not a weakly prime, because it can be changed into another prime (221302997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110651496 + 110651497.

It is an arithmetic number, because the mean of its divisors is an integer number (110651497).

Almost surely, 2^221302993 is an apocalyptic number.

It is an amenable number.

221302993 is a deficient number, since it is larger than the sum of its proper divisors (1).

221302993 is an equidigital number, since it uses as much as digits as its factorization.

221302993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 31.

The square root of 221302993 is about 14876.2560141993. The cubic root of 221302993 is about 604.8705348729.

It can be divided in two parts, 2213029 and 93, that added together give a palindrome (2213122).

The spelling of 221302993 in words is "two hundred twenty-one million, three hundred two thousand, nine hundred ninety-three".