221869561 has 2 divisors, whose sum is σ = 221869562. Its totient is φ = 221869560.

The previous prime is 221869547. The next prime is 221869579. The reversal of 221869561 is 165968122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 220344336 + 1525225 = 14844^2 + 1235^2 .

It is a cyclic number.

It is not a de Polignac number, because 221869561 - 2⁹ = 221869049 is a prime.

It is a super-2 number, since 2×221869561² = 98452204196665442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (221861561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110934780 + 110934781.

It is an arithmetic number, because the mean of its divisors is an integer number (110934781).

Almost surely, 2^221869561 is an apocalyptic number.

It is an amenable number.

221869561 is a deficient number, since it is larger than the sum of its proper divisors (1).

221869561 is an equidigital number, since it uses as much as digits as its factorization.

221869561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 40.

The square root of 221869561 is about 14895.2865363510. The cubic root of 221869561 is about 605.3862806468.

The spelling of 221869561 in words is "two hundred twenty-one million, eight hundred sixty-nine thousand, five hundred sixty-one".