221736869 has 2 divisors, whose sum is σ = 221736870. Its totient is φ = 221736868.

The previous prime is 221736841. The next prime is 221736877. The reversal of 221736869 is 968637122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 220908769 + 828100 = 14863^2 + 910^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221736869 is a prime.

It is a super-2 number, since 2×221736869² = 98334478147846322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221736839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110868434 + 110868435.

It is an arithmetic number, because the mean of its divisors is an integer number (110868435).

Almost surely, 2^221736869 is an apocalyptic number.

It is an amenable number.

221736869 is a deficient number, since it is larger than the sum of its proper divisors (1).

221736869 is an equidigital number, since it uses as much as digits as its factorization.

221736869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 44.

The square root of 221736869 is about 14890.8317094782. The cubic root of 221736869 is about 605.2655701786.

The spelling of 221736869 in words is "two hundred twenty-one million, seven hundred thirty-six thousand, eight hundred sixty-nine".