221993669 has 2 divisors, whose sum is σ = 221993670. Its totient is φ = 221993668.

The previous prime is 221993647. The next prime is 221993671. The reversal of 221993669 is 966399122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 181225444 + 40768225 = 13462^2 + 6385^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221993669 is a prime.

It is a super-2 number, since 2×221993669² = 98562378152163122, which contains 22 as substring.

Together with 221993671, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221993689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110996834 + 110996835.

It is an arithmetic number, because the mean of its divisors is an integer number (110996835).

Almost surely, 2^221993669 is an apocalyptic number.

It is an amenable number.

221993669 is a deficient number, since it is larger than the sum of its proper divisors (1).

221993669 is an equidigital number, since it uses as much as digits as its factorization.

221993669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 314928, while the sum is 47.

The square root of 221993669 is about 14899.4519697873. The cubic root of 221993669 is about 605.4991386632.

The spelling of 221993669 in words is "two hundred twenty-one million, nine hundred ninety-three thousand, six hundred sixty-nine".